Turner's family immigrated to Canada in 1932, and Turner gained his early education in Ottawa. After graduating in political science from the University of British Columbia (A.B., 1949), he studied for a year in Paris and attended the University of Oxford as a Rhodes scholar, receiving a degree in law in 1952 and a master's degree in 1957.

Turner returned to Canada and worked for various corporations, winning his first election to the House of Commons as a Liberal Party member in June 1962. In 1965 he was appointed to his first cabinet post but lost a bid for leadership of the Liberals in 1968 to Trudeau. Under Trudeau, Turner first served as justice minister and in 1972 was appointed minister of finance, a post he abruptly resigned in September 1975, followed by his resignation from Parliament in February 1976. He returned to corporate law and for the next eight years also served as director of several companies while retaining close connections with political associates.

When Trudeau announced in February 1984 that he would not seek reelection as head of the Liberal Party, Turner ran for the leadership and won. His premiership, however, was brief, lasting less than three months, since the general elections he called were won by the Progressive Conservatives. Turner resigned as leader of the Liberal Party in 1989 after his party lost a second general election to the Conservatives in the previous year.