[4] On 14 December 1976, Fullerton was appointed president of the bank, succeeding Russell Edward Harrison.

[6] In 1980, amid struggles at the bank, Fullerton attempted to a coup to seize Harrison's office.

Harrison punished Fullerton for his insubordination by stripping him of the chief operating officer role, and assigning him to work on strategic planning.

Fullerton devised a plan to streamline the bank, which was, according to an insider, the "answer to the board's prayer.

[9] At this time, Harrison was in the rare position of being the bank's president, chairman, and chief executive.

Fullerton retired as chairman and chief executive on 7 June 1992, and was succeeded in both roles by Alvin Flood.

He served as a director of IBM Canada, Amoco Canada, North American Life, Husky Oil, Westcoast Transmission Company, Honeywell, George Weston, Alcan, Coca-Cola, Ontario Hydro, Wellesley Hospital, Canadian Eastern Finance, and Massey Ferguson.

[11] On 10 April 1954 at Rosedale Presbyterian Church, Fullerton married Charlotte Knowlton Lyle (1930–1974).