Eastwood was born in San Francisco to Clinton Eastwood, Sr. (1906–70), a steelworker and migrant worker, and Margaret Ruth (née Runner; 1909–2006), a factory worker. He was nicknamed "Samson" by the hospital nurses as he weighed 11 pounds 6 ounces (5.2 kg) at birth. After his father died in 1970, Eastwood's mother remarried to John Belden Wood (1913–2004) in 1972, and they remained married until his death 32 years later. Eastwood is of English, Irish, Scottish, and Dutch ancestry and was raised in a middle class home with his younger sister, Jean (born 1934). His family relocated often as his father worked at different jobs along the West Coast, including at a pulp mill. The family settled in Piedmont, California, where Eastwood attended Piedmont Junior High School and Piedmont Senior High School, taking part in sports such as basketball, football, gymnastics, and competitive swimming. He later transferred to Oakland Technical High School where the drama teachers encouraged him to enroll in school plays, but he was not interested. As his family moved to different areas he held a series of jobs including lifeguard, paper carrier, grocery clerk, forest firefighter, and golf caddy.
Eastwood registered as a Republican in order to vote for Dwight D. Eisenhower in 1952 and he supported Richard Nixon's 1968 and 1972 presidential campaigns. He later criticized Nixon's handling of the Vietnam War and his morality during Watergate. He usually describes himself as a libertarian in interviews, fiscally conservative yet socially liberal. He told USA Weekend in 2004, "I don't see myself as conservative, but I'm not ultra-leftist. ... I like the libertarian view, which is to leave everyone alone. Even as a kid, I was annoyed by people who wanted to tell everyone how to live."