<PAGE>

                                                                     EXHIBIT 4.2

                              AMENDED AND RESTATED
                                     BYLAWS
                                       OF
                         GREENE COUNTY BANCSHARES, INC.

                                     OFFICE

1.    Principal Office

      The principal office of the Corporation shall be in Greeneville,
      Tennessee, and the Corporation shall have such other offices at such other
      places within or without the State of Tennessee as the Board of Directors
      may from time to time determine or as the business of the Corporation may
      require.

                             SHAREHOLDERS' MEETINGS

2.    Annual Meeting

      An annual meeting of the shareholders of the Corporation shall be held on
      such date as may be determined by the Board of Directors. The business to
      be transacted at such meeting shall be the election of directors and such
      other business as shall be properly brought before the meeting. If the
      election of directors shall not be held on the day designated by the Board
      of Directors for any annual meeting, or at any adjournment of such
      meeting, the Board of Directors shall call a special meeting of the
      shareholders as soon as conveniently possible thereafter. At such special
      meeting the election of directors shall take place and such election and
      any other business transacted thereat shall have the same force and effect
      as if transacted at an annual meeting duly called and held.

3.    Special Meetings

      Special meetings of the shareholders may only be called by the Board of
      Directors or a committee duly designated by the Board of Directors.

4.    Place of Meetings

      Annual and special meetings of the shareholders shall be held at the
      Corporation's principal office or at such other place within or without
      the State of Tennessee as may be designated by the Board of Directors.

5.    Notice of Meetings; Waiver

      (a)   Annual Meetings. Written or printed notice stating the place, day
            and hour of the annual meeting of shareholders shall be given in
            person or by mail to each shareholder of record entitled to vote at
            such meeting. If mailed, such notice shall be delivered not less
            than ten (10) days nor more than two (2) months before the meeting.
            Mailed notice shall be deemed to be delivered when deposited, with
            postage prepaid, in the United States mail addressed to the
            shareholder at his address as it appears on the records of the
            Corporation at the close of business on the record date established
            for such meeting. If delivered personally, such notice shall be
            delivered not less than ten (10) days nor more than two (2) months
            before the date of the meeting and shall be deemed delivered when
            actually received by the shareholder.

      (b)   Special Meetings. Written or printed notice of every special meeting
            of shareholders shall be given in person or by mail to each
            shareholder of record entitled to vote at such meeting. Such notice
            shall state the place, day, hour, purpose or purposes for which the
            meeting is called, and the person or persons calling the meeting. If
            mailed, such notice shall be delivered not less than ten (10) days
            nor more than two (2) months before the meeting. Mailed notice shall
            be deemed to be delivered when deposited, with postage prepaid, in
            the United States mail addressed to the

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                                                                     EXHIBIT 4.2

            shareholder at his address as it appears on the records of the
            Corporation at the close of business on the record date established
            for such meeting. If delivered personally, such notice shall be
            delivered not less than ten (10) days nor more than two (2) months
            before the date of the meeting and shall be deemed delivered when
            actually received by the shareholder.

      (c)   Waiver. A shareholder may waive the notice of either an annual or a
            special meeting by the submission by the shareholder or his proxy
            holder of a written waiver of notice either before or after such
            meeting.

6.    Quorum

      Except as otherwise required by law or provided in these Bylaws, a quorum
      at any meeting of shareholders shall consist of the holders of record of a
      majority of the shares issued and outstanding and entitled to vote
      thereat, present in person or by proxy. If, however, such majority shall
      not be present or represented at any meeting of the shareholders, the
      shareholders present in person or by proxy and entitled to vote thereat
      shall have power to adjourn the meeting from time to time, and to any
      other place, without notice other than announcement at the meeting of the
      time and place to which the meeting is adjourned. At any adjourned meeting
      at which the requisite amount of voting stock to constitute a quorum shall
      be represented, any business may be transacted which might have been
      transacted at the meeting as originally called.

7.    Record Date

      The record date for the determination of shareholders entitled to notice
      of and entitled to vote at any meeting of shareholders or any adjournment
      thereof, shall be such date as shall be determined by the Board of
      Directors, but which in any event shall not be less than ten (10) days
      prior to the date of such meeting. If the Board of Directors does not fix
      such record date, the record date for the determination of shareholders
      entitled to notice of and entitled to vote at any meeting of shareholders
      or at any adjournment thereof shall be the close of business on the day
      next preceding the day on which notice is given.

8.    Voting of Shares

      Unless otherwise provided in the Charter, each shareholder of the
      Corporation shall be entitled, at each meeting of the shareholders and
      upon each proposal presented at such meeting, to one vote for each share
      of the capital stock having voting power registered in his name on the
      books of the Corporation on the record date. Each shareholder having the
      right to vote shall be entitled to vote in person or by proxy appointed by
      an instrument in writing executed by such shareholder or his duly
      authorized attorney-in-fact and bearing a date not more than eleven (11)
      months prior to said meeting, unless said instrument provides for a longer
      period. Unless the Charter, these Bylaws or applicable law specifically
      provide otherwise, the affirmative vote of a majority of shares
      represented and entitled to vote at a meeting at which a quorum is present
      shall be the act of the shareholders, except that directors shall be
      elected by a plurality of the votes cast in the election. At each election
      of directors, every shareholder shall have the right to vote the number of
      shares which he is entitled to vote at such meeting for as many persons as
      there are directors to be elected at said meeting, but cumulative voting
      for such nominees shall not be permitted unless the Charter otherwise
      provides.

9.    Presiding Officer

      Meetings of the shareholders shall be presided over by the Chairman, or if
      he is not present, by the President, or if he is not present, by a Vice
      President, or if neither the Chairman, President nor a Vice President is
      present, by a chairman to be chosen by a majority of the shareholders
      entitled to vote at such meeting. The Secretary of the Corporation or, in
      his absence, an Assistant Secretary shall act as secretary of every
      meeting, but if neither the Secretary nor an Assistant Secretary is
      present, the shareholders entitled to vote at such meeting shall choose
      any person present to act as secretary of the meeting.

                                    DIRECTORS

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                                                                     EXHIBIT 4.2

10.   Powers and Duties

      The business and affairs of the Corporation shall be managed by the Board
      of Directors. In addition to the powers and authority expressly conferred
      upon them by these Bylaws, the Board may exercise all the powers of the
      Corporation and do all lawful acts and things as are not by applicable
      law, by the Charter of the Corporation or by these Bylaws directed or
      required to be exercised or done by the shareholders.

11.   Number, Classification, Term, Qualification, and Vacancies

      (a)   Number, Classification and Term. The Board of Directors shall
            consist of eleven (11) members. The Board of Directors shall be
            divided into three classes equal in number. The members of each
            class shall be elected for a term of three (3) years and until their
            successors are elected and qualified, except during an interim
            arrangement immediately following adoption of the provisions in the
            Corporation's Charter regarding the Classified Board. One (1) class
            shall be elected by ballot annually.

      (b)   Vacancies. In case there are vacancies on the Board of Directors,
            other than vacancies created by the removal of a director or
            directors (which shall be governed by paragraph 15(c)), the
            remaining directors may by a majority vote of the directors then in
            office elect a successor or successors who shall hold office until
            his or their successors are elected or qualified.

      (c)   Qualification. Directors must be of legal age and be shareholders of
            the Corporation.

      (d)   Retirement of Directors. No person 70 years of age or older shall be
            eligible for election, re-election, appointment or re-appointment as
            a director of the Company. No director shall serve beyond the annual
            meeting of the Company immediately following the director becoming
            70 years old, and such director shall thereafter be a retired
            director of the Company. The Board of Directors, at its discretion,
            may name retired directors to the classification of Director
            Emeritus, who may attend meetings but will not have any vote or any
            liability for serving.

12.   Quorum

      A majority of the total number of directors in office shall constitute a
      quorum for the transaction of business. If, at any meeting of the Board of
      Directors, there shall be less than a quorum present, a majority of those
      present may adjourn the meeting, without further notice, from time to time
      until a quorum shall have been obtained.

13.   Manner of Acting

      The act of a majority of the directors present at a meeting at which a
      quorum is present shall, unless otherwise provided by applicable law or
      these Bylaws, be the act of the Board of Directors. Any action required or
      permitted to be taken at a meeting of directors may be taken without a
      meeting if a consent in writing, setting forth the action so taken, is
      signed by all the directors. Such written consent shall have the same
      force and effect as a unanimous vote at a meeting of the Board of
      Directors.

14.   Meetings; Notice

      Meetings of the Board of Directors may be held either within or without
      the State of Tennessee. Notice of a meeting of the Board of Directors need
      not state the purpose of, nor the business to be transacted at, such
      meeting.

      (a)   Regular Meetings. Regular meetings of the Board of Directors shall
            be held at such times as are fixed from time to time by resolution
            of the Board, and may be held without notice of the time or place
            therefor.

      (b)   Special Meetings. Special meetings may be held at any time upon call
            of the Chairman, the

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                                                                     EXHIBIT 4.2

            President, a Vice President or any two (2) directors. Notice of the
            time and place of each special meeting shall be given to each
            director at either his business or residence address, as shown by
            the records of the Corporation, at least forty-eight (48) hours
            prior thereto if mailed and on the day prior thereto if delivered or
            given in person or by telephone or telegraph. If mailed, such notice
            shall be deemed to be delivered when deposited, so addressed and
            with postage prepaid, in the United States mail. If notice is given
            by telegram, such notice shall be deemed to be delivered when the
            telegram, so addressed, is delivered to the telegraph company. If
            notice is given in person, such notice shall be deemed to have been
            given when it is hand delivered to the director at his business or
            residence address. Any director may waive notice of any meeting
            before, at or after such meeting and the attendance of a director at
            a meeting shall constitute a waiver of notice of such meeting except
            when a director attends for the sole, express purpose of objecting
            to the transaction of business thereat, on the ground that the
            meeting is not lawfully called or convened, and so states in writing
            prior to the conduct of any business at the meeting.

15.   Removal

      (a)   By Shareholders. Unless the Charter otherwise provides, at any
            meeting of the shareholders, the entire Board of Directors or any
            number of directors may be removed from office, with or without
            cause, by a majority vote of the shares represented and entitled to
            vote thereat.

      (b)   By Directors. At any meeting of the Board of Directors, any director
            or directors may be removed from office for cause, as that term is
            defined by applicable law, by a majority of the entire Board of
            Directors.

      (c)   Replacement. When any director or directors are removed, new
            directors may be elected to fill the vacancies created thereby at
            the same meeting of the shareholders or Board of Directors, as the
            case may be, for the unexpired term of the director or directors
            removed. If the shareholders fail to elect persons to fill the
            unexpired term or terms of the director or directors removed by
            them, such unexpired terms shall be considered vacancies on the
            Board to be filled by the remaining directors as provided in
            paragraph 11(b).

16.   Compensation

      Directors, and members of any committee of the Board of Directors, shall
      be entitled to such reasonable compensation for their services as
      directors and members of any such committee as shall be fixed from time to
      time by resolution of the Board of Directors, and shall also be entitled
      to reimbursement for any reasonable expenses incurred in attending such
      meetings. Any director receiving compensation under these provisions shall
      not be barred from serving the Corporation in any other capacity and
      receiving reasonable compensation for such other services.

                                   COMMITTEES

17.   Executive Committee

      There may be, if so determined by a resolution adopted by a majority of
      the entire Board of Directors, an Executive Committee of the Board
      consisting of two (2) or more directors. The Board of Directors may
      delegate to such Executive Committee all the power and authority of the
      Board that it deems desirable, except for any matters which cannot by law
      be delegated by the Board of Directors. Unless specifically authorized by
      the Board, the Executive Committee shall not have the power to adopt,
      amend or repeal these Bylaws, to submit to shareholders any matter that by
      law requires their authorization, to fill vacancies in the Board of
      Directors or in any committee or to declare dividends or make other
      corporate distributions.

18.   Other Committees

      The Board of Directors may create such other committees as it may
      determine to be helpful in discharging its responsibilities for the
      management and administration of the Corporation. Each such committee
      shall consist of such persons, whether directors, officers or others, as
      may be elected thereto by the Board of

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                                                                     EXHIBIT 4.2

      Directors, and each committee shall perform such functions as may be
      lawfully assigned to it by the Board of Directors.

                                    OFFICERS

19.   Number

      The officers of the Corporation shall be a Chairman, a President, a
      Secretary and such other officers as may be from time to time elected by
      the Board of Directors. One person may hold more than one office except
      the President may not hold the office of Secretary.

20.   Election and Term of Office

      The principal officers shall be elected annually by the Board of Directors
      at the first meeting of the Board following the shareholders' annual
      meeting, or as soon thereafter as is conveniently possible. Subordinate
      officers may be elected from time to time. Each officer shall serve at the
      pleasure of the Board for such term as the Board of Directors may set and
      until his successor shall have been elected and qualified, or until his
      death, resignation or removal.

21.   Removal

      Any officer may be removed from office by the Board of Directors whenever
      in its judgment the best interests of the Corporation will be served
      thereby, but such removal shall not prejudice the contract rights, if any,
      of the persons so removed.

22.   Vacancies

      Any vacancy in an office from any cause may be filled for the unexpired
      portion of the term by the Board of Directors.

23.   Duties

      (a)   Chairman. The Chairman shall preside at all meetings of the
            shareholders or directors and have such other duties as the Board of
            Directors may designate from time to time and shall see that all
            orders and resolutions of the Board of Directors are carried into
            effect. If the Board shall so determine, the Chairman may be the
            Chief Executive Officer of the Corporation.

      (b)   Chief Executive Officer. The Chief Executive Officer shall be
            responsible for carrying out the orders of and the resolutions and
            policies adopted by the Board of Directors and shall have general
            management of the business of the Corporation and shall exercise
            general supervision over all of its affairs. In addition, the Chief
            Executive Officer shall have such powers and perform such duties as
            may be provided for herein and as are normally incident to the
            office and as may be prescribed by the Board of Directors. If and at
            such time as the Board of Directors so determines, the Chief
            Executive Officer may also serve as the Chairman, or the President
            of the Corporation.

      (c)   President. The President shall be the Chief Executive Officer of the
            Corporation unless the Board of Directors has appointed another
            person to such office, in which case the President shall be the
            Chief Operating Officer of the Corporation and shall have such
            powers and perform such duties as may be provided for herein and as
            are normally incident to the office and as may be prescribed by the
            Board of Directors, the Chairman of the Board, or the Chief
            Executive Officer.

      (d)   Vice President. The Executive Vice President and the Senior Vice
            President/Chief Financial Officer (if any) shall be active executive
            officers of the Corporation, shall assist the President in the
            active management of the business, and shall perform such other
            duties as the Board of Directors may from time to time prescribe.

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                                                                     EXHIBIT 4.2

      (e)   Secretary. The Secretary shall attend all meetings of the Board of
            Directors and all meetings of the shareholders and record all votes
            and the minutes of all proceedings in a book to be kept for that
            purpose; he shall perform like duties for any committee when
            required. The Secretary shall give, or cause to be given, notice of
            all meetings of the shareholders and of the Board of Directors when
            required, and unless directed otherwise by the Board of Directors,
            shall keep a stock record containing the names of all persons who
            are shareholders of the Corporation, showing their place of
            residence and the number of shares held by them respectively. The
            Secretary shall perform such other duties as may be prescribed from
            time to time by the Board of Directors.

      (f)   Other Officers. Other officers appointed by the Board of Directors
            shall exercise such powers and perform such duties as may be
            delegated to them by the Board of Directors.

      (g)   Delegation of Duties. In case of the absence or disability of any
            officer of the Corporation or of any person authorized to act in his
            place, the Board of Directors may from time to time delegate the
            powers and duties of such officer to any officer, or any director,
            or any other person whom it may select, during such period of
            absence or disability.

24.   Indemnification of Officers and Directors

      The Corporation shall indemnify each present and future director and
      officer of the Corporation, or any person who may have served at its
      request as a director or officer of another company (and, in either case,
      his heirs, executors and administrators) to the full extent allowed by the
      laws of the State of Tennessee, both as now in effect and as hereafter
      adopted unless otherwise prohibited by federal law or regulations.

                        CERTIFICATES FOR SHARES OF STOCK

25.   Form

      (a)   Stock Certificates. The interest of each shareholder of the
            Corporation shall be evidenced by a certificate or certificates for
            shares of stock. The certificate shall include the following on its
            face: (i) the Corporation's name, (ii) the fact that the Corporation
            is organized under the laws of the State of Tennessee, (iii) the
            name of the owner of record of the shares represented thereby, (iv)
            the number of shares represented thereby, (v) the class of shares
            and the designation of the series, if any, which the certificate
            represents, (vi) the par value of each share or a statement that the
            shares are without par value, and (vii) such other information as
            applicable law may require or as may be lawful.

      (b)   Signatures. The certificates for stock shall be signed by the
            President and by the Secretary. Where any certificate is manually
            countersigned by a transfer agent or registered by a registrar who
            is not an officer or employee of the Corporation, the signatures of
            the President and the Secretary may be facsimiles, engraved or
            printed. In case any officer who has signed, or whose facsimile
            signature has been placed upon, any certificate shall have ceased to
            be such before the certificate is issued, it may be issued by the
            Corporation with the same effect as if such officer had not ceased
            to be such at the time of its issue.

26.   Subscriptions for Shares

      Subscriptions for shares of the Corporation shall be valid only if they
      are in writing, signed and delivered by the subscriber. Unless the
      subscription agreement provides otherwise, subscriptions for shares,
      regardless of the time when they are made, shall be paid in full at such
      time, or in such installments and at such periods, as shall be determined
      by the Board of Directors. All calls for payments on subscriptions shall
      be uniform as to all shares of the same class or of the same series.

27.   Transfers

      Transfers of shares of the capital stock of the Corporation shall be made
      only on the books of the

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                                                                     EXHIBIT 4.2

      Corporation by (i) the holder of record thereof, (ii) by his legal
      representative, who shall furnish proper evidence of authority to
      transfer, or (iii) his attorney, authorized by a power of attorney duly
      executed and filed with the Secretary of the Corporation or a duly
      appointed transfer agent. Such transfers shall be made only upon surrender
      of the certificate or certificates for such shares properly endorsed and
      with all taxes thereon paid.

28.   Lost, Destroyed, or Stolen Certificates

      No certificate for shares of stock of the Corporation shall be issued in
      place of any certificate alleged to have been lost, destroyed, or stolen
      except on production of evidence, satisfactory to the Board of Directors,
      of such loss, destruction or theft, and, if the Board of Directors so
      requires, upon the furnishing of an indemnity bond in such amount (but not
      to exceed twice the value of the shares represented by the certificate)
      and with such terms and such surety as the Board of Directors may in its
      discretion require.

                                CORPORATE ACTIONS

29.   Contracts

      Unless otherwise required by the Board of Directors, the Chairman and/or
      the Chief Executive Officer, the President or any Vice President shall
      execute contracts or other instruments on behalf of and in the name of the
      Corporation. The Board of Directors may from time to time authorize any
      other officer or officers or agent or agents to enter into any contract or
      execute any instrument in the name of and on behalf of the Corporation as
      it may deem appropriate, and such authority may be general or confined to
      specific instances.

30.   Loans

      No loans shall be contracted on behalf of the Corporation and no evidence
      of indebtedness shall be issued in its name unless authorized by the Board
      of Directors. Such authority may be general or confined to specific
      instances.

31.   Checks, Drafts, etc.

      Unless otherwise required by the Board of Directors, all checks, drafts,
      bills of exchange and other negotiable instruments of the Corporation
      shall be signed by either the Chairman, the Chief Executive Officer, the
      President, the Secretary, Assistant Secretary, the Senior Vice
      President/Chief Financial Officer, or their designees, in each case to the
      extent authorized to do so by the Board of Directors. Such authority may
      be general or confined to specific business, and, if so directed by the
      Board, the signatures of two or more such officers may be required.

32.   Deposits

      All funds of the Company not otherwise employed shall be deposited from
      time to time to the credit of the Corporation in such banks or other
      depositories as the Board of Directors may authorize.

33.   Voting Securities Held by the Corporation

      Unless otherwise required by the Board of Directors, the Chairman or the
      President shall have full power and authority on behalf of the Corporation
      to attend any meeting of security holders, or to take action on written
      consent as a security holder, of other corporations in which the
      Corporation may hold securities. In connection therewith the Chairman or
      the President shall possess and may exercise any and all rights and powers
      incident to the ownership of such securities which the Corporation
      possesses. The Board of Directors may, from time to time, confer like
      powers upon any other person or persons.

34.   Dividends

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                                                                     EXHIBIT 4.2

      The Board of Directors may, from time to time, declare, and the
      Corporation may pay, dividends on its outstanding shares of capital stock
      in the manner and upon the terms and conditions provided by applicable
      law. The record date for the determination of shareholders entitled to
      receive the payment of any dividend shall be determined by the Board of
      Directors, but which in any event shall not be less than ten (10) days
      prior to the date of such payment.

                                   FISCAL YEAR

35.   The fiscal year of the Corporation shall be determined by the Board of
      Directors, and in the absence of such determination, shall be the calendar
      year.

                                 CORPORATE SEAL

36.   The Corporation shall not have a corporate seal.

                              AMENDMENT OF BYLAWS

37.   These Bylaws may be altered, amended or repealed, and new Bylaws may be
      adopted at any meeting of the shareholders by the affirmative vote of a
      majority of the stock represented at such meeting, or by the affirmative
      vote of a majority of the members of the Board of Directors who are
      present at any regular or special meeting; provided, however, that any
      amendment to these Bylaws changing the number of directors, if adopted by
      the Board of Directors, shall require the affirmative vote of a majority
      of the members of the entire Board of Directors.

                                       8