Born in London, Ontario, Holmes attended the University of Western Ontario and received a Master of Arts degree from the University of Toronto. From 1933 to 1938, he was a master of English at Pickering College. From 1938 to 1940, he attended the University of London. He joined the Department of External Affairs in 1943 as a temporary wartime assistant.[2]
From 1947 to 1948, he was the Canadian Chargé d'Affaires ad interim to the Soviet Union. In 1950, he was appointed Acting Permanent Delegate to the United Nations.[3] He became Assistant Under-Secretary of State for External Affairs in 1953 where he remained until he was forced to resign from the department, in 1960, after admitting to being a homosexual. From 1960 to 1973, Holmes was president (later called director-general) of the Canadian Institute of International Affairs,[4] a non-partisan, non-profit, and non-governmental organization for the discussion and analysis of international affairs.[5]
Holmes was among hundreds of federal civil servants who were targeted in an RCMP homosexual witch hunt that intensified in 1958 and continued through to the mid-1990s, destroying lives, careers and families.[6]
From 1971 to 1981, he was a professor of international relations at York University, Glendon College. From 1967 until his death, he was a visiting professor of international relations at the University of Toronto. He was also a visiting professor of history at the University of Leeds in 1979 and 1985.[7]
He was the author of Life with Uncle: the Canadian-American Relationship (1981) and The Shaping of Peace: Canada and the Search for World Order 1943-1957 (2 volumes, 1979 and 1982). In 1986, he was awarded the Royal Society of Canada's J. B. Tyrrell Historical Medal in recognition of these volumes.[8]
In 1969, he was made an Officer of the Order of Canada.[9] He was a Fellow of the Royal Society of Canada and the recipient of 10 honorary doctorates.[4]
