Léger's first assignment was as a priest in the parish of Notre-Dame in Montreal. After joining the Society of Saint-Sulpice in September 1929 he was sent to its noviciate in Issy-les-Moulineaux for his period of solitude in 1929–1930. He then spent a year at the Institut Catholique de Paris studying canon law. Léger then taught this for a year after earning his bachelor's degree in 1931. He then become assistant master at the noviciate the following year.
