 He served as professor, rector and superior at St. Charles Scholasticate in Battleford, Saskatchewan, and as professor of moral theology at Newman Theological College in Edmonton, Alberta.He entered the religious institute of the Missionary Oblates of Mary Immaculate in 1950 in St. Norbert, Manitoba and was ordained as a priest in 1957.In 1974, Exner was appointed Bishop of Kamloops and in 1982, Archbishop of Winnipeg.