Kate Walsh first dabbled in acting while studying at the University of Arizona. After working as a model, she moved to Chicago, appearing in regional stage productions. She then moved to New York and participated in several off-Broadway stagings.
Walsh made her on-screen debut in the 1996 film Normal Life. The following year, she nabbed her first major television role, when she joined the cast of The Drew Carey Show as Carey's formerly obese girlfriend Nicki Fifer. She also held recurring roles in The Norm Show and The Mind of the Married Man, and was also part of the cast of the ill-fated sitcom The Mike O'Malley Show. One of her notable early dramatic roles was on CSI, as a transsexual.
In 2005 Walsh joined the cast of the ABC medical drama Grey's Anatomy, as Addison Montgomery, the estranged wife of Patrick Dempsey's Derek Shepherd. Her character's success led producers to pen a spin-off series for her: Private Practice premiered in 2007, although she still makes occasional appearances on the main series.
Walsh married movie executive Alex Young in 2007, but they were divorced three years later.
- She was bulemic as a young girl.
- She served one night in jail for throwing a pool cue ball at a mirror.
- She wore a fat suit in her role as Nicki Fifer on The Drew Carey Show.
- Her mother is Italian and her father is Irish.
- She wore glasses as a child.
- During the early 1980s, she became a model in Japan.
2007: Screen Actors Guild Awards - Outstanding Performance by an Ensemble in a Drama Series for: Grey's Anatomy. Shared.
2007-2011: Private Practice (TV series) - Dr. Addison Montgomery/Dr. Addison Forbes Montgomery
2010: Funny or Die Presents... (TV series) - Cast (Holdup)
2010: Legion - Sandra Anderson
2005-2010: Grey's Anatomy (TV series) - Dr. Addison Montgomery-Shepherd/Dr. Addison Montgomery
2009: One Way to Valhalla - Raina
2009: King of the Hill (TV series) - Katt Savage
2008: Upright Citizens Brigade: Asssscat (TV movie) - Guest Monologist
2007: 1408 - Mike Enslin's ex-wife
2007: Girl Missing (video) - Abbie Pennington
2007: Veritas, Prince of Truth - Nemesii
2006: Cheap Seats: Without Ron Parker (TV series) - Rochelle
2005: Bewitched - Sexy Waitress
2005: Inside Out - Tyne
2005: Kicking & Screaming - Barbara Weston
2005: Eyes (TV series) - Kendall Judd
2005: Bobby Cannon (TV movie) - London
2004: Wake Up, Ron Burgundy: The Lost Movie (video) - Sue
2004: Complete Savages (TV series) - Maggie
2004: CSI: Crime Scene Investigation (TV series) - Mimosa
2004: After the Sunset - Sheila
2003: Karen Sisco (TV series) - Marley Novak/Sgt. Marley Novak
2004: The Men's Room (TV series) - Karen
2004: Joint Custody (TV series) - Florence
2003: Under the Tuscan Sun - Grace
2003: Untitled Nicole Sullivan Project (TV movie)
1997-2002: The Drew Carey Show (TV series) - Nicki Fifer/Nicki Fifer Carey
2002: A Day in the Life of Nancy M. Pimental (video short) - Kate
2002: Anatomy of a Breakup - Lorra
2001: The Mind of the Married Man (TV series) - Carol Nelson
2001: The Fugitive (TV series) - Agent Eve Hilliard/Eve Hilliard
2000-2001: The Norm Show (TV series) - Jenny
2000: The Family Man - Jeannie
2000: Cursed (TV series) - Stace
2000: The Only Living Boy in New York (TV movie)
1999: The Mike O'Malley Show (TV series) - Marcia
1999: Turks (TV series) - Terry
1998: Cupid (TV series) - Heidi
1998: Heaven - Restaurant Trio
1998: Three Below Zero - Moriat Greenberg
1997: Night of the Lawyers - Pressie Brooks (Biker)
1997: Law & Order (TV series) - Lt. Kirstin Blair
1997: Peppermills (short) - Lena
1996: Henry: Portrait of a Serial Killer, Part 2 - Cricket
1996: Swift Justice (TV series) - Paula 'Paulie' Goddard
1996: Homicide: Life on the Street (TV series) - Cathy Buxton
1996: Normal Life - Cindy Anderson
1995: Club Dead (Video Game) (voice)