David Marquette Kopay was born on June 28, 1942 in Chicago, Illinois and grew up in Southern California. The second of four children in a strict Catholic family, Kopay was an altar boy before he started playing football at Notre Dame High School in Sherman Oaks. He was recruited to Marquette University and transferred to the University of Washington in 1961, where he was a running back and co-captain, leading the football team to the Rose Bowl in 1964.

Kopay played football professionally in the National Football League (NFL) for nine seasons, first for the San Francisco 49ers (1964-1967), Detroit Lions (1968), Washington Redskins (1969-1970), New Orleans Saints (1971), and Green Bay Packers (1972) before retiring in 1972.

After years of struggling with his sexual identity, Kopay came out as gay on December 11, 1975 in an article by Lynn Rosellini in the Washington Star. He faced a backlash from upset fans, but also received support from others struggling with similar situations. He applied for football coaching and scouting jobs, but was never hired, possibly due to the revelation of his sexual orientation. In 1977 he teamed up with Perry Deane Young to publish an autobiography titled The David Kopay Story: An Extraordinary Self-Revelation.

Kopay moved to California and worked at Linoleum City, a family business, while continuing to speak out publicly about gay rights on and off the football field. He became a Gay Games Ambassador (2006) and featured speaker at the International Conference on Ethical Issues in Sport (1998), and in 2007 pledged an endowment of $1 million to the University of Washington’s Q Center.