Following the war, Seaborn returned to the Anglican Church of Canada, serving as Rector of the Anglican Cathedral of the Holy Trinity,
Quebec City and
Dean of Quebec, (1948–57), Rector of St. Mary's Kerrisdale
Vancouver,
British Columbia (1957–58), and in both
Corner Brook and
St. John's,
Newfoundland. Bishop Seaborn was the 15th Metropolitan of the Ecclesiastical Province of Canada, serving from 1975 to 1980. In 1976 he oversaw reorganization of the one Newfoundland diocese into three - the Diocese of Eastern Newfoundland and Labrador with its cathedral at St. John's, the Diocese of Central Newfoundland (Gander) and the Diocese of Western Newfoundland (Corner Brook). This made him the 8th and final Bishop of Newfoundland and the only one to be named Metropolitan of Canada. During the 1960s he was involved in the integration of the Anglican, United Church, Salvation Army, and Presbyterian educational services in Newfoundland. Along with his wife, Mary Elizabeth (Betty), he spearheaded the founding of KillDevil Camp in
Gros Morne National Park in Western
Newfoundland. The camp's central building has since been named Seaborn Lodge. Seaborn later returned to
Ontario and served as chancellor of
University of Trinity College at the
University of Toronto from 1982 to 1990 and Bishop Ordinary to the
Canadian Forces from 1980 to 1986. Bishop Seaborn died in
Cobourg,
Ontario on February 15, 1993. His brother,
J. Blair Seaborn, was a longtime Canadian civil servant and diplomat. ==Honorary degrees==