 He was elected to represent Saint-Maurice in the Legislative Assembly of Canada in 1854, 1858 and 1861 as a member of the parti bleu, then was defeated in 1863.He was elected to the 1st Canadian Parliament in 1867 but resigned in 1868 to become inspector for prisons and asylums in Quebec, later serving as president of that agency.Desaulniers also was an officer in the local militia.