Joseph was the twin brother of Sister Marie Levasseur. Their father was Hilaire Levasseur and their mother Adéline Pelletier, sister of Father Joseph Pelletier. Second young man from Saint-Basile to become a priest, Joseph was ordained in Chatham by Bishop Rogers in 1885. He was the parish priest of Tracadie for thirty-four years. Then he retired at Hôtel-Dieu of his parish. Father Levasseur left generous donations for the orphans of the convent of Saint-Basile, where he went to school as a child.