Justin W. Chambers (born July 11, 1970) is an American actor and former Calvin Klein male fashion model. As of 2005, he is starring in the ABC drama series Grey's Anatomy as Dr. Alex Karev. Chambers was born in Springfield, Ohio, the son of deputy police officers Pam and John Chambers. He has a fraternal twin brother named Jason, one older brother John Jr. (Chip), and two older sisters, Mia and Susan. He and his twin brother visited hospitals often as children due to frequent bouts with pneumonia. He attended Southeastern High School in South Charleston, Ohio. In 1993, he married Keisha, a former model agency booker. The couple have five children: Isabella (b. December 1994), twins Maya and Kaila (b. June 1997), Eva (b. March 1999) and Jackson (b. 2002). His wife and children have recently moved to Los Angeles from their home in a suburb just outside of New York City. In late January 2008, Chambers admitted that he suffered from biological sleep disorder. The actor checked himself into Los Angeles' UCLA Medical Center to treat exhaustion due to the sleep disorder after a period of getting only two hours of sleep each week.
Chambers was discovered by a modeling scout on the Paris Metro and went on to represent Calvin Klein in a fragrance campaign. He worked throughout Europe, Japan, and the United States for CK, Armani, and Dolce & Gabbana. After deciding on an acting career, he moved to New York, where he studied at H.B. Studios for four years. That landed him a few television roles, including Another World and New York Undercover. More recently, he starred in several movies, notably The Wedding Planner (2001, alongside Jennifer Lopez), The Musketeer (2001) Southern Belles (2005), The Zodiac (2005), Lakeview Terrace (2008) and the HBO original movie Hysterical Blindness (2002). Chambers was cast as one of the leads in the CBS crime drama Cold Case but left after appearing in only four episodes. Now he plays resident Alex Karev on the hit ABC medical show Grey's Anatomy. In 2006, he was awarded a Screen Actors Guild Award along with his fellow cast members for an 'Outstanding Performance by an Ensemble in a Drama Series.' He guest-starred on the Grey's Anatomy spin-off Private Practice for the Grey's Anatomy/Private Practice Crossover Event. His first major acting role came in the music video "Ants Marching" by Dave Matthews Band in 1994. Appeared on episode of Extreme Makeover: Home Edition, helping build a home for the Almquiest family.