MacGibbon began her career in pure mathematics, at
McGill University. She earned a master's degree there in 1966, working with Michael Herschorn on
differential equations, and completed a Ph.D. in 1970, with a dissertation on
topology supervised by
Donald A. Dawson. As well as McGill and the Université du Québec à Montréal, she has also been affiliated with the Department of Decision Sciences and Management Information Systems at
Concordia University in Montreal, where she was hired in 1986. By 1993 she had moved to the Université du Québec à Montréal. ==Research==