Walsh worked at fast-food outlets before modeling and teaching English in Japan in the 1980s. Later, she moved to
Chicago and worked with the
Piven Theatre Workshop. She performed on
National Public Radio in the production of the radio play
Born Guilty. Walsh founded Boyfriend LLC, a beauty and lifestyle company, in 2010.
Television roles After playing Cathy Buxton in the
Homicide: Life on the Street episode "Stakeout" in 1996 and Navy Lieutenant Kirstin Blair in the
Law & Order episode "Navy Blues," Walsh's first major television appearance was in 1997, when she appeared on
The Drew Carey Show as
Drew Carey's love interest,
Nicki Fifer. She wore a
fatsuit in some episodes of the show. Walsh 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. She made a guest appearance on
CSI: Crime Scene Investigation as Mimosa, a
transgender woman. She sometimes appeared in sketches on ''
Late Night with Conan O'Brien''. Walsh had a recurring role on
Karen Sisco as Detective Marley Novak in 2003 and 2004. In 2005, she was cast in her breakout role in the ABC series ''
Grey's Anatomy, as Dr. Addison Montgomery, the estranged spouse of Derek Shepherd ("Dr. McDreamy," played by Patrick Dempsey). In February 2007, her Grey's Anatomy
character received a spin-off of Grey's Anatomy
that began airing in September 2007. Taye Diggs, Tim Daly, Amy Brenneman, Chris Lowell, and Audra McDonald were cast in the spin-off, Private Practice''. However, she mentioned she'd be open to reprise her role in ''Grey's Anatomy'' for a few guest spots. In 2013, Walsh appeared in
Full Circle, a 10-episode ensemble drama series created by
Neil LaBute and airing on
DirecTV's
Audience Network channel. In 2014, Walsh had a supporting role in the first season of FX's television series
Fargo. She had a guest starring role in Hulu's original series
The Hotwives of Orlando and later starred in the NBC series
Bad Judge, which aired for one season. From 2017 to 2019, Walsh starred in the Netflix drama series
13 Reasons Why, as the mother of a child who dies by suicide. Her performance was met with critical acclaim, having been dubbed the "best work" of her career. In 2019 and 2020, Walsh had a significant recurring role as "the Handler" in the
Netflix series
The Umbrella Academy. Her most recent role has been on Netflix Original,
Emily in Paris, where she plays Emily's boss who gets pregnant and can no longer move to Paris for their marketing job, so she sends Emily instead. In September 2021, Walsh announced she would be reprising her role as Dr. Addison Montgomery in the
eighteenth season of ''Grey's Anatomy'' in a guest starring role. In 2026, it was announced that Walsh would play the lead role in
CBS sitcom pilot
The Tillbrooks. Walsh was set to star opposite John Cusack in the supernatural thriller
1408, but had to drop out due to scheduling conflicts. Walsh starred in the biblical horror film
Legion, that was released on January 22, 2010. She played Charlie's mother in
The Perks of Being a Wallflower.
Theatre In May 2010, Walsh made her
off-Broadway debut opposite Paul Sparks in Atlantic Theater Company's world premiere of
Stephen Belber's
Dusk Rings a Bell. The new play began previews on May 19 and opened May 27 at Atlantic Stage 2 and played through June 26.
The New York Times called it "a sublime, beautifully acted drama." She also had a long theater career in Chicago, which included roles in
Happy Birthday Wanda June,
The Danube,
Moon Under Miami and
Troilus and Cressida. In New York, Walsh was a member of the
improvisational comedy troupe Burn Manhattan and the New York City Players theater ensemble. ==Personal life==