<PAGE>

                                                                   Exhibit 10.15
                             EMPLOYMENT AGREEMENT

     AGREEMENT, made as of the 1st day of November, 2000, is entered into by and
among BSB Bancorp, Inc., a Delaware corporation (the "Corporation"), BSB Bank &
Trust Company, a New York chartered bank and trust company (the "Employer") and
John B. Westcott (the "Executive").

     WHEREAS, the Corporation, the Employer and the Executive desire to enter
into this Agreement to provide for the continued employment of the Executive as
the Administrative Vice President and Senior Credit Officer of the Employer;

     WHEREAS, the parties desire to enter into this Agreement, setting forth the
terms and conditions for the employment relationship of the Executive with the
Employer:

     NOW, THEREFORE, it is AGREED as follows:

     1.  Employment.  The Executive shall be employed as the Administrative Vice
         ----------
President and Senior Credit Officer of the Employer and shall serve in such
capacity during the Employment Term (as defined in Section 5 below).  As the
Administrative Vice President and Senior Credit Officer of the Employer, the
Executive shall render executive, policy and other management services to the
Employer of the type customarily performed by persons serving in a similar
officer capacity and shall report to the Chief Executive Officer of the
Employer, except as such Chief Executive Officer reasonably shall otherwise
determine.  The Executive shall also perform such duties as the Chief Executive
Officer of the Employer or the Board of Directors of the Employer (the "Board")
may from time to time reasonably direct.

     2.  Compensation.
         ------------

          (a) The Employer agrees to pay the Executive during the Employment
Term (defined below) a salary at an annual rate not less than $105,000.  The
Executive's salary shall be increased in the sole and absolute discretion of the
Board or committees thereof duly authorized by the Board to so act.

          (b) The salary of the Executive shall not be decreased at any time
during the Employment Term from the amount then in effect, unless the Executive
otherwise agrees in writing.  Participation in deferred compensation,
discretionary bonus, retirement and other employee benefit plans and in fringe
benefits, other than salary reduction programs in which the Executive elects to
participate, shall not reduce the salary payable to the Executive under this
Section 2.  The salary under this Section 2 shall be payable to the Executive
not less frequently than monthly.

     3.  Business Expenses.  To the extent that the Employer authorizes the
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Executive to incur business expenses, including the reasonable costs of
authorized business entertainment and travel, in connection with the performance
of his duties hereunder, the Employer shall reimburse the Executive for such
authorized expenses promptly upon periodic presentation by the Executive of an
itemized account of such expenses and reasonable substantiation, in accordance
with the Employer's policies concerning reimbursement of business expenses.

     4.  Participation in Retirement and Employee Benefit Plans; Fringe
         --------------------------------------------------------------
Benefits.  During the Employment Term, the Executive shall be eligible to
participate in all incentive, bonus, management recognition, equity
compensation, retirement, deferred compensation, fringe benefit or welfare
benefit plans of the Company or the Employer that are applicable to executive
employees of the Employer generally, including plans providing for stock
options, restricted stock, employee stock purchases, pension or retirement
income, retirement savings, employee stock ownership, deferred compensation and
medical, prescription drug, dental, disability, employee life, group life,
accidental death and travel accident insurance that the Company or the Employer
may adopt or maintain for the benefit of executive employees of the Employer
during the Employment Term, in accordance with the terms of such plans.

     5.  Term.  The term of employment under this Agreement shall commence on
         ----
the date of this Agreement and shall end on October 31, 2001, provided that the
Employer may extend the term of employment
<PAGE>

under this Agreement for one additional year on each annual anniversary date of
this Agreement, by giving written notice of such extension to the Executive not
less than 30 days in advance of any such anniversary date. The initial term of
employment and all such renewed terms of employment under this Agreement are
collectively referred to herein as the "Employment Term".

     6.  Standards.  The Executive shall perform his duties and responsibilities
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under this Agreement in accordance with such reasonable standards as may be
established from time to time by the Board and communicated in writing to the
Executive.  The reasonableness of such standards shall be measured against
standards for executive performance generally prevailing in the financial
institutions industry.

     7.  Voluntary Absences; Vacations.  The Executive shall be entitled,
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without loss of pay, to absent himself voluntarily for reasonable periods of
time from the performance of his duties and responsibilities under this
Agreement.  All such voluntary absences shall count as paid vacation time,
unless the Board otherwise approves.  The Executive shall be entitled to paid
vacation days totaling 20 business days per year.  The timing of paid vacations
shall be scheduled in a reasonable manner by the Executive.

     8.  Termination of Employment.
         -------------------------

          (a)   (i)     Subject to the other provisions of this Agreement, the
Employer may terminate the Executive's employment at any time.

                (ii) The Executive shall have no right to receive compensation
or other benefits for any period after he voluntarily terminates of his
employment without "Good Reason" (as defined below) or the Employer
involuntarily terminates his employment for Cause. "Cause" shall mean the
Executive's personal dishonesty, willful misconduct, breach of fiduciary duty
involving personal profit, willful failure to perform stated duties, willful
violation of any law, rule, or regulation (other than traffic violations or
similar offenses) or final cease-and-desist order of the Federal Deposit
Insurance Corporation ("FDIC") or a material breach of any provisions of this
Agreement. For purposes of this paragraph, no act, or failure to act, on the
Executive's part shall be considered "willful" unless done, or omitted to be
done, by him not in good faith and without reasonable belief that his action or
omission was in the best interest of the Employer; provided that any act or
omission to act on the Executive's behalf in reliance upon an opinion of counsel
satisfactory to the Employer shall not be deemed to be willful.

                (iii)  The parties acknowledge and agree that damages that will
result to the Executive for involuntary termination without Cause shall be
extremely difficult or impossible to establish or prove, and agree that, subject
to Section 11 of this Agreement, unless such involuntary termination is for
Cause, the Employer shall be obligated, following such termination, to continue
to pay to the Executive compensation in accordance with Section 2 hereof for the
remaining term of this Agreement. The amounts payable hereunder shall not be
reduced by the Executive's earnings from other employment or self-employment
after termination of his employment with the Employer. The Executive agrees
that, except for such other payments and benefits to which the Executive may be
entitled as expressly provided by the terms of this Agreement, the payments
provided for under this Section 8(a)(iii) shall constitute liquidated damages
and shall be in complete satisfaction of the Employer's obligations under this
Agreement.

                (iv) In addition to the liquidated damages above described that
are payable to the Executive, subject to Section 11 of this Agreement, in the
event of any such termination without Cause, during the period in which payments
are required to be made under Section 8(a)(iii) above, or such longer period as
may be provided by the terms of the appropriate plan, the Employer shall
continue in effect all medical, prescription drug, dental, disability, employee
life, group life and accidental death insurance and other employee welfare plans
for the benefit of the Executive and, if applicable, the Executive's family,
which would have been provided to them in accordance with Section 4 of this
Agreement if the Executive's employment had not been terminated; provided,
however, that if the Executive is eligible to receive medical, prescription drug
or dental benefits under an employee benefits plan sponsored by a subsequent
employer, the medical prescription drug and dental benefits described herein
shall be secondary to those provided under such other plan during such
applicable period of eligibility.
<PAGE>

                (v) If the Executive voluntarily terminates his employment with
the Employer during the Employment Term for "Good Reason," such termination
shall be deemed to have been an involuntary termination by the Employer of the
Executive's employment without Cause. "Good Reason" shall mean:

                        (1) the assignment to the Executive by the Employer of
duties materially inconsistent with the Executive's position, duties,
responsibilities, and status as Administrative Vice President and Senior Credit
Officer of the Employer, a material adverse change in the Executive's titles or
offices, any removal of the Executive from or any failure to reelect the
Executive to any of such officer positions, except in connection with the
termination of his employment for Cause, or any action that would have a
material adverse effect on the physical conditions in which or location at which
the Executive performs his employment duties;

                        (2) a reduction by the Employer in the Executive's
salary under Section 2(a) without the Executive's consent; or

                        (3) any other action or inaction that constitutes a
material breach by the Employer of this Agreement.

          (b) The Executive shall have no right to terminate his employment
under this Agreement before the end of the Employment Term, unless (i) such
termination is approved by the Board or (ii) such termination is with "Good
Reason" as defined above.  In the event that the Executive violates this
provision, the Employer shall be entitled, in addition to its other legal
remedies, to enjoin the employment of the Executive with any significant
competitor of the Employer for a period of one year or the then remaining
Employment Term plus six months, whichever is less.  The term "significant
competitor" shall mean any commercial bank, savings bank, savings and loan
association, mortgage banking company or a holding company affiliate of any of
the foregoing which, at the date of its employment of the Executive, has an
office out of which the Executive would be primarily based that is located
within 75 miles of the Employer's office located at 58-68 Exchange Street,
Binghamton, New York.  If any court or other tribunal having jurisdiction to
determine the validity or enforceability of this paragraph determines that,
strictly applied, it would be invalid or unenforceable, the definition of
"significant competitor" and the time provisions used shall be deemed modified
to the extent necessary (but only to that extent) so that the restrictions in
that subsection, as modified, will be valid and enforceable.

          (c) In the event the employment of the Executive is terminated by the
Employer without Cause under Section 8(a) hereof and the Employer fails to make
timely payment of the amounts then owed to the Executive under this Agreement,
the Executive shall be entitled to reimbursement for all reasonable costs,
including attorneys' fees, incurred by the Executive in taking action to collect
such amounts or otherwise to enforce this Agreement, plus interest on such
amounts at the rate of one percent above the prime rate (defined as the base
rate on corporate loans at large U.S. money center commercial banks as published
by The Wall Street Journal), compounded monthly, for the period from the date of
employment termination until payment is made to the Executive.  Such
reimbursement and interest shall be in addition to all rights which the
Executive is otherwise entitled to under this Agreement.

          (d) In the event of the Executive's death during the Employment Term,
his estate shall be entitled to receive any unpaid salary or other compensation
owing to the Executive.  This Agreement shall thereupon terminate, except that
any vested rights of the Executive shall then be exercised by his estate.

          (e) In the event the Executive becomes disabled during the Employment
Term under circumstances that would entitle him to benefits under the Employer's
long-term disability plan and, as a result of such disability, he is unable to
perform his duties hereunder for an uninterrupted period of more than six
months, the Employer may terminate the Executive's employment without liability
under Section 8(a) hereof and this Agreement shall thereupon terminate.  Any
such termination shall not affect the Executive's rights to benefits pursuant to
any applicable long-term disability plan of the Employer.

          (f) Notwithstanding any other provision in this Agreement, (i) the
Employer may terminate or suspend this Agreement and the employment of the
Executive hereunder, as if such termination were for Cause
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under Section 8(a) hereof, to the extent required by the applicable laws of the
State of New York related to banking, by applicable federal law relating to
deposit insurance or bank holding companies or by regulations or orders issued
by the New York State Banking Department, the Board of Governors of the Federal
Reserve System, the Federal Deposit Insurance Corporation or other state or
federal banking regulatory agency having jurisdiction over the Corporation or
the Employer and (ii) no payment shall be required to be made to or for the
benefit of the Executive under this Agreement to the extent such payment is
prohibited by applicable law, regulation or order issued by a banking agency or
a court of competent jurisdiction; provided, that it shall be the Employer's
burden to prove that any such action was so required.

     10.  Confidential Information.
          ------------------------

          (a) The Executive acknowledges that the information, observations and
data obtained by the Executive concerning the business and affairs of the
Employer during the course of the Executive's employment are the property of the
Employer, including information concerning acquisition opportunities in or
reasonably related to the business or industry of the Employer of which the
Executive becomes aware during such period.  Therefore, the Executive agrees
that he will not at any time (whether during or after the Employment Term)
disclose to any unauthorized person or, directly or indirectly, use for the
Executive's own account, any of such information, observations or data without
the consent of the Board, unless and to the extent that the aforementioned
matters become generally known to and available for use by the public other than
as a direct or indirect result of the Executive's unauthorized acts or omissions
to act or the unauthorized acts or omissions to act of other employees of the
Employer.  The Executive agrees to deliver to the Employer at the termination of
the Executive's employment, or at any other time the Employer may request in
writing (whether during or after the Employment Term), all memoranda, notes,
plans, records, reports and other documents, regardless of the format or media
(and copies thereof), relating to the business of the Employer and its
predecessors (including, without limitation, all acquisition prospects, lists
and contact information) which the Executive may then possess or have under the
Executive's control.

          (b) The Executive acknowledges that the restrictions contained in this
Section 10 hereof are reasonable and necessary, in view of the nature of the
Employer's business, in order to protect the legitimate interests of the
Employer, and that any violation thereof would result in irreparable injury to
the Employer.  Therefore, the Executive agrees that in the event of a breach or
threatened breach by the Executive of the provisions of Section 10(a) hereof,
the Employer shall be entitled to obtain from any court of competent
jurisdiction, preliminary or permanent injunctive relief restraining the
Executive from disclosing or using any such confidential information.  Nothing
herein shall be construed as prohibiting the Employer from pursuing any other
remedies available to them for such breach or threatened breach, including,
without limitation, recovery of damages from the Executive.
<PAGE>

          11.  Section 280G Gross-Up Payment.
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                (a) Anything in this Agreement to the contrary notwithstanding
and except as set forth below in this Section 11(a), in the event it shall be
determined that any payment or distribution by the Employer, or any other member
of the affiliated group (as determined for purposes of Sections 280G and 4999 of
the Internal Revenue Code of 1986, as amended (the "Code") of which the Employer
or the Corporation is a member, to or for the benefit of the Executive (whether
paid or payable or distributed or distributable pursuant to the terms of this
Agreement or otherwise, but determined without regard to any additional payments
required under this Section 11) (a "Payment") would be subject to the excise tax
imposed by Section 4999 of the Code or any interest or penalties are incurred by
the Executive with respect to such excise tax (such excise tax, together with
any such interest and penalties, are hereinafter collectively referred to as the
"Excise Tax"), then the Executive shall be entitled to receive an additional
payment (a "Gross-Up Payment") in an amount such that after payment by the
Executive of all taxes (including any interest or penalties imposed with respect
to such taxes), including, without limitation, any income taxes (and any
interest and penalties imposed with respect thereto) and Excise Tax imposed upon
the Gross-Up Payment, the Executive retains an amount of the Gross-Up Payment
equal to the Excise Tax imposed upon the Payments. Notwithstanding the foregoing
provisions of this Section 11(a), if it shall be determined that the Executive
is entitled to a Gross-Up Payment, but that the Executive, after taking into
account the Payments and the Gross-Up Payment, would not receive a net after-tax
benefit of at least $10,000 (taking into account both income taxes and any
Excise Tax) as compared to the net after-tax proceeds to the Executive resulting
from an elimination of the Gross-Up Payment and a reduction of the Payments, in
the aggregate, to an amount (the "Reduced Amount") such that the receipt of
Payments would not give rise to any Excise Tax, then no Gross-Up Payment shall
be made to the Executive and the Payments, in the aggregate, shall be reduced to
the Reduced Amount.

                (b) Subject to the provisions of Section 11(c), all
determinations required to be made under this Section 11, including whether and
when a Gross-Up Payment is required and the amount of such Gross-Up Payment and
the assumptions to be utilized in arriving at such determination, shall be made
by PriceWaterhouseCoopers LLP or such other certified public accounting firm
reasonably acceptable to the Employer as may be designated in writing by the
Executive (the "Accounting Firm") which shall provide detailed supporting
calculations both to the Employer and the Executive within 15 business days of
the receipt of notice from the Executive that there has been a Payment, or such
earlier time as is requested by the Employer. In the event that the Accounting
Firm is serving as accountant or auditor for the individual, entity or group
effecting the Change of Control, the Executive shall appoint another nationally
recognized accounting firm reasonably acceptable to the Employer to make the
determinations required hereunder (which accounting firm shall then be referred
to as the Accounting Firm hereunder). All fees and expenses of the Accounting
Firm shall be borne solely by the Employer. Any Gross-Up Payment, as determined
pursuant to this Section 11, shall be paid by the Employer to the Executive
within five business days of the receipt of the Accounting Firm's determination.
Any determination by the Accounting Firm shall be binding upon the Employer and
the Executive. As a result of the uncertainty in the application of Section 4999
of the Code at the time of the initial determination by the Accounting Firm
hereunder, it is possible that the initial Gross-Up Payments made by the
Employer will be inadequate and that additional Gross-Up Payments by the
Employer should have been made ("Underpayment"), consistent with the
calculations required to be made hereunder. In the event that the Employer
exhaust its remedies pursuant to Section 11(c) and the Executive thereafter are
required to make a payment of any Excise Tax, the Accounting Firm shall
determine the amount of the Underpayment that has occurred and any such
Underpayment shall be promptly paid by the Employer to or for the benefit of the
Executive.

                (c) The Executive shall notify the Employer in writing of any
claim by the Internal Revenue Service that, if successful, would require the
payment by the Employer of a Gross-Up Payment. Such notification shall be given
as soon as practicable but no later than 10 business days after the Executive
receives written notice of such claim and shall apprise the Employer of the
nature of such claim and the date on which such claim is requested to be paid.
The Executive shall not pay such claim prior to the expiration of 30 days
following the date on which the Executive gives such notice to the Employer (or
such shorter period ending on the date that any payment of taxes with respect to
such claim is due). If the Employer notifies the Executive in writing prior to
the expiration of such period that they desire to contest such claim, the
Executive shall:
<PAGE>

                        (i)    give the Employer any information reasonably
requested by the Employer relating to such claim,

                        (ii)   take such action in connection with contesting
such claim as the Employer shall reasonably request in writing from time to
time, including, without limitation, accepting legal representation with respect
to such claim by an attorney selected by the Employer and reasonably acceptable
to the Executive,

                        (iii)  cooperate with the Employer in good faith in
order effectively to contest such claim, and

                        (iv)   permit the Employer to participate in any
proceedings relating to such claim; provided, however, that the Employer shall
bear and pay directly all costs and expenses (including additional interest and
penalties) incurred in connection with such contest and shall indemnify and hold
the Executive harmless, on an after-tax basis, for any Excise Tax or income tax
(including interest and penalties with respect thereto) imposed as a result of
such representation and payment of costs and expenses.

          Without limitation on the foregoing provisions of this Section 11(c),
the Employer shall control all proceedings taken in connection with such contest
and, at its sole option, may pursue or forgo any and all administrative appeals,
proceedings, hearings and conferences with the taxing authority in respect of
such claim and may, at its sole option, either direct the Executive to pay the
tax claimed and sue for a refund or contest the claim in any permissible manner,
and the Executive agrees to prosecute such contest to a determination before any
administrative tribunal, in a court of initial jurisdiction and in one or more
appellate courts, as the Employer shall determine; provided, however, that if
the Employer directs the Executive to pay such claim and sue for a refund, the
Employer shall advance the amount of such payment to the Executive, on an
interest-free basis and shall indemnify and hold the Executive harmless, on an
after-tax basis, from any Excise Tax or income tax (including interest or
penalties with respect thereto) imposed with respect to such advance or with
respect to any imputed income with respect to such advance; and further provided
that any extension of the statute of limitations relating to payment of taxes
for the taxable year of the Executive with respect to which such contested
amount is claimed to be due is limited solely to such contested amount.
Furthermore, the Employer's control of the contest shall be limited to issues
with respect to which a Gross-Up Payment would be payable hereunder and the
Executive shall be entitled to settle or contest, as the case may be, any other
issue raised by the Internal Revenue Service or any other taxing authority.

          (d) If, after the receipt by the Executive of an amount advanced by
the Employer pursuant to Section 11(c), the Executive becomes entitled to
receive any refund with respect to such claim, the Executive shall (subject to
the Employer's continued compliance with the requirements of this Section 11)
promptly pay to the Employer the amount of such refund (together with any
interest paid or credited thereon after taxes applicable thereto).  If, after
the receipt by the Executive of an amount advanced by the Employer pursuant to
Section 11(c), a determination is made that the Executive shall not be entitled
to any refund with respect to such claim and the Employer does not notify the
Executive in writing of its intent to contest such denial of refund prior to the
expiration of 30 days after such determination (or if any such contest shall be
finally determined in a manner adverse to such refund being allowed), then such
advance shall be forgiven and shall not be required to be repaid and the amount
of such advance shall offset, to the extent thereof, the amount of the Gross-Up
Payment required to be paid.

     12.  Miscellaneous.
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          (a) No Assignment.  This Agreement is personal to each of the parties
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hereto.  No party may assign or delegate any of his or its rights or obligations
hereunder without first obtaining the written consent of the other party hereto.
However, in the event of the death of the Executive, all of his rights to
receive payments hereunder shall become rights of his estate as provided in
Section 8(d) hereof.

          (b) Other Contracts.  The Executive shall not, during the Employment
              ---------------
Term, have any other paid employment other than with a subsidiary or affiliate
of the Employer, except with the prior written approval of the Board.
<PAGE>

          (c) Amendments or Additions; Action by Board.  No amendments or
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additions to this Agreement shall be binding unless in writing and signed by all
parties hereto.  The prior approval by a majority affirmative vote of the Board
shall be required in order for the Employer to authorize any amendments or
additions to this Agreement or to give any consents or waivers of provisions of
this Agreement, or to terminate the Executive's employment with or without Cause
under Section 8(a) hereof.

          (d) Section Headings.  The section headings used in this Agreement are
              ----------------
included solely for convenience and shall not affect, or be used in connection
with, the interpretation of this Agreement.

          (e) Severability.  The provisions of this Agreement shall be deemed
              ------------
severable and the invalidity or unenforceability of any provision shall not
affect the validity or enforceability of the other provisions hereof.

          (f) Governing Law.  This Agreement shall be governed by the laws of
              -------------
the United States, where applicable, and otherwise by the laws of the State of
New York other than the choice of law rules thereof.

          (g) Notice.  For the purposes of this Agreement, notices and all other
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communications provided for in the Agreement shall be in writing and shall be
deemed to have been duly given when delivered or mailed by certified or
registered mail, return receipt requested, postage prepaid, addressed, if to the
Employer:

                         BSB BANK & TRUST COMPANY
                         58-68 Exchange Street
                         Binghamton, New York  13902
                         Attention:  Chief Executive Officer

or if to the Executive:  John B. Westcott
                         5 Vermont Avenue
                         Binghamton, New York   13905

or to such other address as either party may have furnished to the other in
writing in accordance herewith, except that notice of change of address shall be
effective only upon receipt.

          (h) Counterparts.  This Agreement may be executed in several
              ------------
counterparts, for the convenience of the parties, but shall constitute one and
the same instrument.

          (i) Express Agreement of Successor Required.  The Employer and the
              ---------------------------------------
Corporation will require any successor (whether direct or indirect, by purchase,
merger, consolidation or otherwise) to all or substantially all of the business
or assets of the Employer or the Corporation to expressly agree to honor this
Agreement without modification and to perform the respective obligations of the
Employer and the Corporation hereunder.
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement,
or caused this Agreement to be duly executed on their behalf, as of the date and
year first above written.


Attest:                               BSB BANK & TRUST COMPANY

/s/ Larry G. Denniston                By  /s/ Thomas L. Thorn
----------------------------          -----------------------------



Attest:                               BSB BANCORP, INC.

/s Larry G. Denniston                 By  /s/ Thomas L. Thorn
----------------------------          -----------------------------




                                      /s/ John B. Westcott
                                      -----------------------------
                                          John B. Westcott
                                          Executive