The subject of Gus Van Sant's new movie is Harvey Milk, a 1970s liberal activist and the first major openly gay politician to be elected in the US.

Milk opens with footage of the 1969 Stonewall riots in New York City, a violent protest by homosexuals against police brutality. Other images of men being beaten by police and crammed into paddy wagons—or hiding their faces from the camera to protect their identities—speak to a time when being gay was illegal or semi-legal in many places and, in general, there was widespread harassment and victimization of homosexuals.

Harvey Milk was born on Long Island, New York, in 1930, the son of Eastern European Jews. The Korean War veteran held jobs on Wall Street and in 1964 worked for the presidential campaign of right-wing Republican Barry Goldwater. Swept up by the "counter-culture" of the 1960s and 1970s, Milk openly acknowledged his sexual orientation and eventually fell in with a bohemian milieu in San Francisco. He became an advocate of gay rights, and finally, ran for public office.

Elected to the San Francisco Board of Supervisors in 1977, Milk was assassinated in November 1978, along with the city's mayor, George Moscone. Van Sant's film essentially recounts Milk's six-year career in San Francisco politics.

Milk (Sean Penn) first appears, toward the end of his life, speaking into a tape recorder in a darkened room. He explains, "If a bullet should enter my brain, let the bullet destroy every closet door" (i.e., impel gays to come "out of the closet".) Milk is recording a personal testament in response to death threats he has been receiving since his unsuccessful campaign for the California State Assembly in 1976.