Johnson first worked as an accountant for General Electric in Montreal and as a vice-president of merchandising for the T. Eaton Company before being named president of Standard Brands Ltd.[3] Johnson negotiated a merger between Standard Brands and Nabisco with Nabisco CEO Bob Schaeberle in 1981.
He was extensively profiled in the book Barbarians at the Gate: The Fall of RJR Nabisco by Wall Street Journal columnists Bryan Burrough and John Helyar, and in the movie of the same name made for HBO.
Until he resigned in March 2009, he was chairman of AuthentiDate Holding Corp., a United States publicly traded company.
The Distinguished Visitors Program at the University of Toronto Centre for the Study of the United States was endowed by Johnson in 2001.
Johnson died on December 29, 2016, at his home in Jupiter, Florida, seventeen days after his 85th birthday[1] from pneumonia.