As archbishop, Pettipas also serves as pastor of the Cathedral of St. John the Baptist, the mother church and episcopal see of the archdiocese.

The Metropolitan has two suffragans : The Archdiocese of Grouard–McLennan was erected on April 8, 1862, as the Apostolic Vicariate of Athabaska Mackenzie, on territory split off from the Diocese of Saint-Boniface.

Faraud and later Grouard were assisted by Isidore Clut who was appointed auxiliary bishop on August 3, 1864, and who served until his death on July 9, 1903.

The majority of Grouard's population moved to High Prairie, the newly established town on the railway.

Shortly after the seat of the vicariate was transferred to McLennan, work began on a new cathedral dedicated to Saint John the Baptist.

On July 13, 1967, the Apostolic Vicariate of Grouard was elevated to the Archdiocese of Grouard–McLennan and made the Metropolitan See of northwestern Canada with the newly elevated Dioceses of Prince George, Mackenzie-Fort Smith and Whitehorse as suffragans, but the Diocese of Prince George was later transferred to the Ecclesiastical Province of British Columbia.

The Archdiocese of Grouard–McLennan remained vacant until the appointment of Arthé Guimond, who had served as archdiocesan administrator, on June 9, 2000.