Karen Summer was born on July 22, 1962 in Los Angeles, California. An only child, Summer grew up in both Tarzana and Encino, California. Karen began her career in show business doing a lot of extra, photo double, and stand-in work for the mainstream movie industry; she worked as a stand-in and production assistant for the hit TV series The Dukes of Hazzard (1979) for three years. After meeting noted adult industry casting director Jim South at an El Torito restaurant on Ventura Boulevard, Summer started out in the adult entertainment industry as a nude model and made her hardcore film debut at age twenty in 1982.

Karen appeared in a slew of adult movies made throughout the 1980's for such top directors as Larry Revene, John Stagliano, Bruce Seven, Kirdy Stevens (Stevens was Summer's all-time favorite director), Svetlana Mischoff, and Jack Remy. After retiring from the adult film industry in the 1990's, Summer continued to work for a while as a feature dancer and burlesque performer before moving to Florida, getting married, and becoming a paralegal. In the wake of divorcing her husband in 2000, Karen went on to work in the health care field.

Karen hosts her own show XXX Porn Star Radio as well as runs her own official interactive website. Summer was inducted into the AVN Hall of Fame, the XRCO Hall of Fame, and Legends of Erotica in 2015.