 He studied at the Seminary of St. Brieuc and was ordained a priest in 1739.In 1741 he left for Canada with another priest, Abbé René-Jean Allenou de Lavillangevin, and the newly appointed bishop for Quebec City, Henri-Marie Dubreil de Pontbriand for whom Briand served as vicar-general.He ministered to the dying at the battle of St. Foy (1760), and after the bishop's death was appointed administrator of the diocese which then included Acadia, Louisiana, and Illinois.