André Bessette, C.S.C., began the construction of St. Joseph, a small chapel on the slopes of Mont Royal near Notre Dame College. Soon the growing number of the congregation made it too small. In 1917 a larger church was completed that had a seating capacity of 1,000. In 1924, the construction of the basilica of Saint Joseph's Oratory was commenced; it was finally completed in 1967.
Father Paul Bellot, an architect, completed the dome of Saint Joseph's Oratory between 1937-39. The dome is the third-largest of its kind in the world after the Basilica of Our Lady of Peace of Yamoussoukro in Côte d'Ivoire and Saint Peter's Basilica in Rome.
Between 1949-51, architect Gilbert Moreau carried out alterations and improvements to the interior of Saint Joseph's Oratory, as well as to the adjacent monastery, and rearranged the sacristy in the basilica.
The basilica is dedicated to Saint Joseph, to whom Brother André credited all his reported miracles. These were mostly related to some kind of healing power, and many pilgrims (handicapped, blind, ill, etc.) poured into his Basilica, including numerous Protestants. On display in the basilica is a wall covered with thousands of crutches from those who came to the basilica and were allegedly healed. Pope John Paul II deemed the miracles to be authentic and beatified Brother André in 1982. In October 2010 Pope Benedict XVI canonized the saint.
A reliquary in the church museum contains Brother André's heart, which he requested as a protection for the basilica. More than 2 million visitors and pilgrims visit the Oratory every year. It is located at 3800 Queen Mary Road, at Côte-des-Neiges (near the Côte-des-Neiges metro station).
Composer Émilien Allard notably served as the church's carillonneur from 1955-1975. For RCA Victor he released the LP album Carols at the Carillon of Saint Joseph's Oratory for which he wrote the arrangements.