Justin Chambers (born July 11, 1970) is an American actor and former fashion model, best known for his role as Dr. Alex Karev in the ABCmedical drama series Grey's Anatomy.

Career
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 Calvin Klein, Armani, and Dolce &Gabbana. After deciding on an acting career, he moved to New York, where he studied at the HB Studio. Studios and Ron Stetson Studios for four years. That landed him a few television roles, including recurring role in soap opera Another World as Nicholas Hudson, and New York Undercover. In 1998 he was cast as series regular in the short-lived CBS primetime soap opera Four Corners. Chambers also appeared in several television movies, such as Harvest of Fire, Rose Hill, and Seasons of Love

Chambers starred in several movies, notably Liberty Heights (1999, as Trey, alongside Adrien Brody),The Wedding Planner (2001, as Massimo, alongside Jennifer Lopez), The Musketeer (2001) Southern Belles (2005), The Zodiac (2005), and the HBO original movie Hysterical Blindness (2002). In 2003, Chambers was cast as one of the leads in the CBS crime drama Cold Case but left after appearing in only four episodes.

In August, 2004, Chambers was cast as surgical intern Alex Karev in ShondaRhimes medical drama series Grey's Anatomy, opposite Ellen Pompeo, Sandra Oh, Katherine Heigl, and T. R. Knight. In 2006, along with other cast members, he was awarded a Screen Actors Guild Award for Outstanding Performance by an Ensemble in a Drama Series. In 2009, he also guest-starred on the Grey's Anatomy spin-off, Private Practice, for the Grey's Anatomy/Private Practice crossover event.