Schwarzenegger was known as the Styrian Oak, or Austrian Oak, in the bodybuilding world, where he dwarfed his competition. He won his first amateur Mr. Universe title in 1967. After moving to California in 1968 to train and compete in bigger events in the United States, he won four more Mr. Universe titles and then the professional Mr. Olympia title six years in a row (1970–75) before retiring. He surprised the bodybuilding world by returning to competition one more time to claim the Mr. Universe title in 1980. Bodybuilding was the subject of several of his books, including the autobiographical Arnold: The Education of a Bodybuilder (1977; cowritten with Douglas Kent Hall) and The New Encyclopedia of Modern Bodybuilding (1998; cowritten with Bill Dobbins).

Meanwhile, Schwarzenegger pursued his childhood dream of acting in movies. In his first film, Hercules in New York (1970), Schwarzenegger played the lead, but another actor was used to dub his dialog. Schwarzenegger's native charm and wit finally came through in the acclaimed documentary Pumping Iron (1977), which led to his starring role in Conan the Barbarian (1982). He became an international star with The Terminator (1984) and its sequels (1991, 2003). His other films include Predator (1987), Kindergarten Cop (1990), Total Recall (1990), True Lies (1994), and The 6th Day (2000).

Schwarzenegger became a U.S. citizen in 1983 and married reporter Maria Shriver in 1986. During the 1990s he became increasingly active in the Republican Party at both state and national levels. In 2003 he was elected governor of California in a recall election.