He practiced law mostly in Quebec for the law firm Cohen, Leithman, Kaufman, Yarosky & Fish which later became Yarosky, Fish, Zigman, Isaacs & Daviault between 1967 and 1989. He also lectured at a number of Canadian law schools. He was appointed to the Quebec Court of Appeal on June 30, 1989 and was appointed to the Supreme Court of Canada on August 5, 2003.