1874–1950, Canadian political leader, b. Kitchener, Ont.; grandson of William Lyon Mackenzie. An expert on labor questions, he served in Wilfrid Laurier's Liberal administration as deputy minister of labor (1900–1908) and minister of labor (1909–11) and was editor (1900–1908) of the Labour Gazette. He first served in the House of Commons from 1909 to 1911, and during World War I he was engaged (1914–17) in investigating industrial relations in the United States. Chosen in 1919 to succeed Laurier as leader of the Liberal party, Mackenzie King led the opposition in Parliament until 1921, when he became prime minister, a post he filled, except for a brief interval in 1926, until 1930. Leader of the opposition during Richard Bedford Bennett's government (1930–35), he afterward again served (1935–48) as prime minister. Called upon to guide Canadian affairs during World War II, King enunciated his position in Canadaat Britain's Side (1941) and Canada and the Fight for Freedom (1944). In 1940 he concluded with President Franklin Delano Roosevelt the Ogdensburg Agreement and in 1941, the Hyde Park Declaration; by these Canada and the United States agreed to create a permanent joint board of defense and to cooperate in the production of defense materials. King served as chairman of the Canadian delegation at the conference (1945) in San Francisco to draft the Charter of the United Nations and at the Paris Conference of 1946. With President Harry Truman and Prime Minister Clement Attlee of Great Britain, he signed in 1945 the Washington declaration on atomic energy.
- See biography by R. M. Dawson (Vol. I, 1958) and H. B. Neatby (Vol. II, 1963);.
- J. W. Pickersgill and D. F. Forster, The Mackenzie King Record (4 vol., 1960–70);.
- Knight of the Holy Spirit: A Study of William Lyon Mackenzie King (1980). ,