Before attending law school, he studied economics, receiving his B.A. from the University of Toronto in 1983 and his Ph.D. from Harvard University in 1989, and he taught for a year in the economics department at Williams College in Massachusetts. He received his LL.B. degree from the University of Toronto in 1992, clerked at the Ontario Court of Appeal in 1992-93, and was called to the Ontario Bar in 1998. From 1998 to 2007, he was an Associate Editor of the Canadian Criminal Cases and the Dominion Law Reports. Professor Stewart is the principal author of Sexual Offences in Canadian Law (Canada Law Book, 2004), the General Editor of Evidence: A Canadian Casebook, 2d ed. (Emond Montgomery, 2006), and the author of more than 40 scholarly papers in criminal law, evidence, legal theory, and economics.