[1] Born in Salisbury, Southern Rhodesia, the son of a British engineer working in Southern Rhodesia, Douglas left as a youngster for England and after the outbreak of World War II was evacuated to Canada with other children during the "Blitz".
During this period, he earned a Master of Arts degree in history at Dalhousie University in 1962, with a thesis on "Halifax as an element of sea power, 1749–1766".
In 1967 he was assigned as an historian at the Directorate of History, National Defence Headquarters, in Ottawa.
During this period he completed graduate studies at Queen's University under Sydney F. Wise, earning a Ph.D. in 1973 with a thesis on "Nova Scotia and the Royal Navy, 1713–1766".
Among his appointments, he was a member of the Public Service Commission Committee of Peers for the Canadian Government Historical Research Group, 1973–1994; national commissioner of Canadian National Commission for Military History; chairman of Canadian Commission for the History of the Second World War, 1973–1984; vice president, 1976–1981, and member of council of North American Society for Oceanic History, 1973–1985; director of Ontario Historical Society, 1975–1983; secretary, 1984–89, and president, 1990–1993 of Canadian Nautical Research Society; adjunct professor at Carleton University, 1985– ; visiting professor of history at Duke University, 1988–89, 2001–02; vice-president of International Commission for Maritime History, 1995–2000; visiting research fellow at Clare Hall, Cambridge, 1996.