For over 67 years St. Denis has been a vibrant center of worship and service for the catholic community of the north end of St. Catharines.

Although St. Denis parish was not canonically established until June 1946, it was clearly realized by the mid-thirties that a new parish was needed to better serve the growing catholic population in the north end of the city. The archbishop of Toronto, most Rev. James McGuigan, in his annual report stated as one of his priorities that a new church should be constructed in St. Catharines, as a memorial to the Right Reverend Denis Morris P.A. as a matter of fact, the same Denis Morris had already purchased a parcel of land on Russell Avenue at the foot of Henry Street as a possible site of a church.

On June 10, 1946, the Archbishop of Toronto, now James Cardinal McGuigan, by formal decree established the parish of St. Denis in the city of St. Catharine’s. As its first pastor, the cardinal appointed Father Leo Smith who had returned after serving as a chaplain with the Canadian Armed Forces in the World War II. He took up residence at Mount Carmel home on Yates Street and began immediately to organize the new parish community in preparation to establish a place of worship.

Father Smith, on the recommendation of Dean Cullihane, called upon the intervention of senator Mr. Joseph J. Bench, a prominent catholic layman in the city, who used his good office to arrange for the purchase of two surplus army barracks from the Department of National Defense at its military camp in Niagara-on-the-Lake. The two buildings were set up side by side on the Russell Avenue property, one serving as the place of worship and the other as a three room school operated by the separate school board.

Having laid the groundwork for the first parish church, Father Smith did not remain to enjoy the fruits of his labour. He was called upon to go to the parish of Holy Name in Toronto. In the summer of 1947, Father Joseph Crothers was named by the Archbishop to carry on the work began by Fr. Smith. His brother, Fr. James Crothers joined him as the Parochial Vicar. In his inimitable jovial way Fr. Joe very quickly endeared himself to his new flock and with their ready and willing support he was able to complete in a relatively short time the restructuring program at the Russell Avenue site. On Sunday, December 14, 1947 the temporary church of St. Denis was opened with Masses at 8:00 a.m., 9:00 a.m., 10:00 a.m., and 11:00 a.m.