Tanaka held several cabinet positions, including minister of finance (1962–1965) and minister of trade and industry (1971–1972). He succeeded Satō Eisaku as prime minister in July 1972.
The advent of Soviet-American détente and America's opening of relations with the People's Republic of China (PRC) beginning in the early 1970s gave Tanaka a chance to improve Japanese relations with both the Soviets and Chinese. After President Richard M. Nixon's historic February 1972 visit to the PRC, Tanaka visited Beijing in September 1972, meeting with Prime Minister Zhou Enlai and establishing diplomatic relations with the PRC. Tanaka also visited Moscow in October 1973, although a joint Japanese-Soviet communiqué issued at the end of the meeting indicated minor progress in improving relations between the two nations.
The 1973–1974 oil crisis presented diplomatic difficulties for Tanaka. Although U.S. Secretary of State Henry A. Kissinger visited Japan in November 1973 to unite the Western powers behind a single policy to deal with the crisis, Japan moved its Middle East policy toward a more pro-Arab stance to ensure a continued flow of oil.
Tanaka was forced to resign as prime minister in December 1974 over alleged financial mismanagement. He was arrested in 1976 and charged with accepting 500 million yen in bribes from the Lockheed Corporation. Even after his conviction in 1983, he continued to lead the LDP's largest faction and thus influenced Japanese politics until his health declined in 1985. Tanaka died in Tokyo on 16 December 1993.
Buckley, Roger. US-Japan Alliance Diplomacy, 1945–1990. New York: Cambridge University Press, 1992.; Hosoya Chihiro and A50 Editorial Committee, eds. Japan and the United States: Fifty Years of Partnership. Tokyo: Japan Times, 2001.; Schaller, Michael. Altered States: The United States and Japan since the Occupation. Oxford: Oxford University Press, 1997.; Welfield, John. An Empire in Eclipse: Japan and the Postwar American Alliance System; A Study in the Interaction of Domestic Politics and Foreign Policy. London: Athlone, 1988.