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                                                                    EXHIBIT 5.1
 
                  [LETTERHEAD OF GOODWIN, PROCTER & HOAR LLP]
                               
                            December 10, 1998     
 
Merkert American Corporation
490 Turnpike Street
Canton, Massachusetts 02021
 
Ladies and Gentlemen:
 
  This opinion is furnished in connection with the filing by Merkert American
Corporation, a Delaware corporation (the "Company"), with the Securities and
Exchange Commission pursuant to the Securities Act of 1933, as amended, of a
Registration Statement on Form S-1 (the "Registration Statement") relating to
5,060,000 shares of common stock, par value $.01 per share, of the Company
(the "Registered Shares"), including 660,000 shares which the Underwriters (as
defined below) have an option to purchase solely for the purpose of covering
over-allotments. Pursuant to that certain Underwriting Agreement by and among
the Company and the underwriters named below (the "Underwriting Agreement"),
the Registered Shares will be offered by the several underwriters (the
"Underwriters") represented by Wheat First Securities, Inc., Cleary Gull
Reiland & McDevitt Inc., and Scott & Stringfellow, Inc.
 
  In connection with rendering this opinion, we have examined the form of the
proposed Underwriting Agreement; the Amended and Restated Certificate of
Incorporation and By-laws of the Company, each as amended to date; such
records of the corporate proceedings of the Company as we deemed material; and
such other certificates, receipts, records and documents as we considered
necessary for the purposes of this opinion. In our examination, we have
assumed the genuineness of all signatures, the legal capacity of natural
persons, the authenticity of all documents submitted to us as certified,
photostatic or facsimile copies, the authenticity of the originals of such
copies and the authenticity of telephonic confirmations of public officials
and others. As to facts material to our opinion, we have relied upon
certificates or telephonic confirmations of public officials and certificates,
documents, statements and other information of the Company or representatives
or officers thereof.
 
  We are attorneys admitted to practice in The Commonwealth of Massachusetts.
We express no opinion concerning the laws of any jurisdiction other than the
laws of the United States of America, The Commonwealth of Massachusetts and
the Delaware General Corporation Law.
 
  Based upon the foregoing, we are of the opinion that when the Underwriting
Agreement is completed (including the insertion therein of pricing terms) and
executed by the Company and the Underwriters, and the Registered Shares are
sold to the Underwriters and paid for pursuant to the terms of the
Underwriting Agreement, the Registered Shares will be duly authorized, validly
issued, fully paid and nonassessable by the Company under Delaware General
Corporation Law.
 
  We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to our firm under the caption
"Legal Matters" in the Prospectus which is a part of the Registration
Statement.
 
                                          Very truly yours,
                                          /s/ Goodwin, Procter & Hoar LLP
 
                                          GOODWIN, PROCTER & HOAR LLP