Pope John Paul II appointed Durocher Auxiliary Bishop of Sault Sainte Marie, Ontario, on January 20, 1997, and designated him as the titular bishop of Ausuaga. Durocher's episcopal consecration took place on March 14, 1997, with Bishop Jean-Louis Plouffe as the principal consecrator.
On April 27, 2002, Durocher was appointed Bishop of Alexandria-Cornwall, Ontario.