Born in 1857 in France he migrated to United States at the age of 15 and later completed his education at the University of Ottawa, joining the Oblates in 1880. He was ordained a priest in 1885 and in 1897 he became the coadjutor of the bishop of New Westminster, Paul Durieu, succeeding him in 1899. In 1908 the diocese of New Westminster was elevated to the rank of the archdiocese of Vancouver and Mgr. Dontenwill became its first archbishop (appointed on September 19th). A day after this appointment, on September 20th, he was elected the superior general of the Oblates and thus had to resign as the archbishop of Vancouver. He led the Congregation methodically, carefully and firmly, both during the difficult period of the First World War, and during the subsequent period of rebuilding.