[4] Beginning in 1946, she studied for two years at the Carnegie Institute of Technology in Pittsburgh, Pennsylvania, where she joined Kappa Alpha Theta sorority and met industrial design student Burt Wells.

[4] At the time known as “Mary Wells,” Berg worked as a copywriter and copy group head at McCann Erickson in 1953, later joining the Lennen & Newell advertising agency's "brain trust".

In her 2002 book, A Big Life in Advertising, Berg cited DDB partners James Edwin Doyle, Maxwell Dane, and William Bernbach as significant influences on her subsequent career.

[1][2] Major WRG clients included American Motors, Cadbury Schweppes, IBM, MCI Communications, Pan American World Airways, Trans World Airlines, Procter & Gamble, Ralston Purina, RC Cola, and Sheraton Hotels and Resorts.

She was selected by U.S. Vice President Nelson Rockefeller to be a member of his Commission on Critical Choices for Americans, and was also invited by U.S. President Gerald Ford to represent business at an Economic Summit in Washington, D.C.[citation needed] After Wells Lawrence stepped down as CEO in 1990, the agency was sold to Boulet Dru Dupuy Petit, and became known as Wells Rich Greene BDDP.

[3] The agency officially ceased operations in 1998, and donated its archive of print and television ads to Duke University's John W. Hartman Center for Sales, Advertising and Marketing History.

She divorced Bert a second time in 1965, and married former Braniff International Airways president Harding Lawrence on November 25, 1967.