Jean-Marc was born in Edmundston NB and spent his early youth in Sackville NB. The family moved to Montreal, and Jean-Marc went to Loyola High School and College. He entered the Jesuits in English Canada in 1958, was ordained in 1967, and spent many years teaching theology at Regis College, the Jesuit faculty of theology at the University of Toronto. Jean-Marc was its president from 1975 to 1982 and the director of the ecumenical federation of schools of theology in the U of T, known as the Toronto School of Theology, from 1992 to 1999.
From 2002 to 2008 Jean-Marc served as provincial superior of the Jesuits in English Canada. Currently, he is the director of the Jesuit Centre of Spirituality in Halifax, Nova Scotia, and the priest-in-charge of the neighbouring parish of St. Patrick's.