Congrégation du Saint-Esprit
Lefebvre's first assignment as a Holy Ghost Father was as a professor at St. John's Seminary in Libreville, Gabon. In 1934 he was made rector of the seminary. On 28 September 1935 he made his perpetual vows. He served as superior of a number of missions of the Holy Ghost Fathers in Gabon. In October 1945 Lefebvre was ordered by the superior general to return to France and take up new duties as rector of the Holy Ghost Fathers seminary in Mortain.