Mansfield, Michael Joseph, 1903–2001, U.S. senator (1953–77), b. New York City. After working (1922–31) as a mining engineer, he taught (1933–42) history at Montana State Univ. before serving (1943–53) as a Democrat in the U.S. House of Representatives. Elected (1952) to the Senate, Mansfield succeeded Lyndon B. Johnson as Senate majority leader and held that post from 1961 until 1977 when he became ambassador to Japan. He retired in 1989. As majority leader he wielded much power and during the 1960s and 70s he helped win the passage of major civil-rights legislation, liberal social reform programs, and important foreign-policy laws. Mansfield had the longest tenure as majority leader of any senator in U.S. history.
See biography by D. Oberdorfer (2003).
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