 Carignan has worked as a lawyer since his admission to the Quebec Bar in 1988, specializing in civil litigation, labour relations, and health and social services law.He is coauthor of Loi sur les décrets de convention collective annotée, published by Wilson & Lafleur in 1990.While practicing, Carignan also taught labour law administration at the Université de Montréal Faculty of Law and at the Université du Québec à Montréal.