Was born in Tulsa, Oklahoma (1943). Son of Frances Clark (baby photographer) and Lewis Clark. Graduated from Central High school in Tulsa, Oklahoma. Attended Layton School of Art in Milwaukee, Wisconsin. Studied under Walter Sheffer and Gerard Bakker. Film debut was the movie Kids. He was already well known for his revolutionary photographic body of work, including the books Tulsa (1971), Teenage Lust (1982), and Perfect Childhood (1992).
Has one son and one daughter. Got into an argument during a dinner with Hamish McAlpine, the British distributor of his upcoming movie Ken Park, over politics. Clark punched him, which prompted McAlpine to pull the movie from the London Festival. A Vietnam veteran His book of photos, Tulsa, inspired several filmmakers and their films: Martin Scorsese's Taxi Driver, Francis Ford Coppola's Rumble Fish, Gus Van Sant's Drugstore Cowboy and Shinya Tsukamoto's Bullet Ballet (1998).