Walsh was born in San Jose, California and grew up in Tucson, Arizona. She comes from an Irish-Italian Catholic home, and later attended the University of Arizona, where she got involved in regional theater. Walsh was also a model in Japan during the 1980's.

Early career When Walsh moved to Chicago, she began working with the Piven Theatre Workshop. She performed on National Public Radio in the production of the radio play Born Guilty. Walsh subsequently moved to New York City and joined the comedy troupe Burn Manhattan on June 27, 1987, performing in a number of Off-Broadway plays.

Her first major television appearance was in 1997, when she appeared on The Drew Carey Show as Carey's character's girlfriend Nicki. She wore a fatsuit in some episodes of the show, as the Nicki character was a formerly obese woman who lost weight & slowly started to gain it back. She went on to portray Carol Nelson in HBO's The Mind of the Married Man television series, and played Norm MacDonald's romantic interest in the sitcom "The Norm Show". Walsh also made a notable guest appearance on CSI: Crime Scene Investigation as Mimosa, a transsexual. She sometimes appeared in sketches on Late Night with Conan O'Brien. She had a recurring role on Karen Sisco as Detective Marley Novak in 2003 and 2004. In 2005, she was cast in the ABC hit, Grey's Anatomy, as Dr. Addison Montgomery, the estranged spouse of Derek Shepherd ("Dr. McDreamy", played by Patrick Dempsey). The role of Addison was originally conceived as a short-term role, but audience response to Walsh, and to the Derek/Meredith/Addison triangle, convinced series creator Shonda Rhimes to expand the role and make Walsh a series regular. It was announced in February 2007 that Walsh and the character of Addison will be in a spin-off of Grey's Anatomy that could begin airing in autumn 2007. Taye Diggs, Tim Daly, Amy Brenneman, and Merrin Dungey have been cast in the spin-off, which has been given the name Private Practice.

The crime drama Normal Life marked her film debut; she played the sister of a bank robber played by Luke Perry. She portrayed a kleptomaniac in the film Peppermills. Walsh also appeared in the cult movie, Henry: Portrait of a Serial Killer, Part 2. She had her first significant role in a major Hollywood production as Will Ferrell's wife in the family comedy, Kicking & Screaming, alongside Robert Duvall and Mike Ditka. Walsh has also appeared in several other films with Ferrell, including Bewitched and an "alternate film" to Anchorman titled, Wake Up, Ron Burgundy: The Lost Movie. In 2003 Walsh appeared in Under the Tuscan Sun, with Diane Lane and Sandra Oh. She played the girlfriend of Sandra Oh's character (Walsh currently co-stars with Oh on Grey's Anatomy). Regarding her various lesbian roles, Walsh said: "Do I give off a girl-on-girl vibe, I wonder? Or is it because I’m tall? I guess the chicks just dig me!"

Walsh's best friend, Nancy Pimental, based the two main characters in her screenplay for the film The Sweetest Thing in part upon her and Walsh. Walsh told Women’s Health she went from blonde to red because she never was a blonde at heart. "Being blonde was always other than what I really am. I thought I wanted to be one of those softer, girly girls. Then I grew out of that. I realized I’d never be a sweet girl. Never." She is the current spokeswoman for Caress and their new line of body wash called Exotic Oil Infusions She appeared on the cover of O at Home (homestyle magazine by Oprah Winfrey) and was credited as being their first covergirl for that magazine. Walsh is currently engaged to Alex Young, a production co-president at 20th Century Fox.

Screen Actors Guild Award: Outstanding Performance by an Ensemble Cast in a TV Series - Drama: Grey's Anatomy (2007) Best Actress 2002 - Short Film (Model Trapper) - New York International Independent Film & Video Festival Voted number 52 of Maxim's Hot 100 of 2007

One Way to Valhalla (2006) Bewitched (2005) Kicking & Screaming (2005) Veritas, Prince of Truth (2005) Inside Out (2005) Wake Up, Ron Burgundy: The Lost Movie (2004) After the Sunset (2004) Under the Tuscan Sun (2003) Revealing Hollywood: Exposing Writer Nancy M. Pimental, from The Sweetest Thing (DVD, 2002) Anatomy of a Breakup (2002) The Family Man (2000) Heaven (1998) Three Below Zero (1998) Henry: Portrait of a Serial Killer, Part 2 (1998) Night of the Lawyers (1997) Peppermills (1997) Normal Life (1996)

Private Practice (2007-2008) Grey's Anatomy (2005-2008) Eyes (2005) Fugitive (2001)

• Wikipedia: Kate Walsh