Born the son of an electrician in a paper-and-pulp town northeast of Quebec city, Mulroney grew up bilingual in English and French and received a B.A. (1959) from Saint Francis Xavier University, Antigonish, N.S., and a law degree (1962) from Laval University, Quebec city. In 1965 he began practicing law in Montreal, becoming a labour specialist. In 1974 he gained local celebrity as a member of the Cliche Commission investigating crime in Quebec's construction industry. Always active in politics, he made a bid in 1976 for the leadership of the Progressive Conservatives but lost to Joe Clark. In 1977 he was chosen president of the Iron Ore Co. of Canada.

When Mulroney won election as leader of the Progressive Conservative Party at its convention in June 1983, he had never run for or been elected to public office, but he offered the public a new face from French-speaking Quebec, where the Tories had traditionally been weak. He became prime minister in 1984 in a landslide victory of the Progressive Conservatives over the Liberals and was reelected in 1988.

As prime minister, Mulroney sought closer cooperation with the United States on such bilateral issues as trade policies and measures to deal with acid rain in North America. During the early years of his administration Canada's economic growth was strong, job creation was high, and inflation was kept under control. His government pursued deregulation of key industries and reform of the tax structure, though a steep federal tax on goods and services introduced in 1991 was widely unpopular.

Mulroney's political success was in part forged by his creation of what turned out to be a short-term coalition of Quebec nationalists and western conservatives, and his terms were marked by his continuing efforts to unify the country while recognizing Quebec's status as a “distinct society.” In 1987 he negotiated the Meech Lake accord on constitutional revision, but he was unable to obtain ratification from all 10 provinces before the deadline expired in 1990. A second attempt resulted in the Charlottetown accord of 1992; these were accepted by all the provincial premiers but were defeated in a popular referendum later that year. Early in 1993 Mulroney announced his retirement from politics; he was succeeded as party leader and prime minister by Kim Campbell that June.