James Blair Seaborn, diplomat and civil servant, was born in Toronto on March 18, 1924, the son of Richard Seaborn, an Anglican priest, and his wife Muriel. He was educated at the Toronto Normal School, the University of Toronto Schools, and in 1941 he entered Trinity College. In 1943 he enlisted in the army, training with the Royal Canadian Artillery. He served briefly in England and Holland, returning home in 1946. He received his BA in 1947, and an MA in political economy in 1948. While at Trinity College he met Carol Trow (4T8); they married in 1950 and had two children, Geoffrey (Trinity 7T3) and Virginia (Trinity 7T6).
Seaborn joined the Department of External Affairs in 1948, working for e newly appointed Secretary of State for External Affairs, Lester B. Pearson, taking on positions at home and abroad. From 1950 to 1954 he was Second Secretary in The Hague, followed by a promotion to First Secretary in Paris from 1957 to 1959. These positions were followed by a stint in Moscow as Counsellor (1959-1962), and Head, Eastern European Section from 1962-64, and 1966-67, back in Ottawa. Between these last two postings Seaborn served as Canadian Commissioner, International Commission for Supervision and Control, in Saigon. In 1964 and 1965 he was sent on six missions to Hanoi. From 1967 to 1970, back in Ottawa, Seaborn was Head of the Far Eastern Division.
Leaving External Affairs he moved to the Department of Consumer and Corporate Affairs, serving as Assistant Deputy Minister, Consumer Affairs, from 1970 to 1974. He then moved to the Department of the Environment, as Deputy Minister from 1974 to 1982. He was Canadian Chairman of the International Joint Commission from 1982 to 1985, and Intelligence and Security Co-ordinator in the Privy Council Office from 1985 to 1989. In 1989 he retired from the Public Service of Canada.
Post-retirement, Seaborn joined the Canadian Environmental Assessment Agency as Chairman, Environmental Assessment Panel on Nuclear Fuel Waste Management and Disposal Concept. He was actively involved in the Five Lakes Fishing Club in the Gatineau area, and participated in yearly hikes along the Appalachian Trail in New England. He became a resource for countless researchers on the Vietnam War, and on environmental issues, contributing to many articles, interviews, conferences, and broadcasts. In 2000 he became a Member of the Order of Canada. His wife, Carol, predeceased him on June 27, 2011; Blair Seaborn died on November 11, 2019, in Ottawa.