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 La Bute and airing on Direc TV's Audience Network channel.She also briefly returned for one episode in season 6 and two episodes in the seventh and eighth seasons.She continued playing the character of Addison Montgomery on the fourth season of Private Practice, for which ABC ordered a full season of episodes.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. It was announced in February 2007 that Walsh's Grey's Anatomy character would be in a spin-off of Grey's Anatomy that began airing in September 2007.Later she moved to Chicago and worked with the Piven Theatre Workshop.She also performed on National Public Radio in the production of the radio play Born Guilty.
She portrayed a kleptomaniac in the film Peppermills.
She has participated in numerous Planned Parenthood activities, including national fundraisers, local Planned Parenthood affiliate events, the PPFA Awards Gala, and lobby day on Capitol Hill promoting the need for comprehensive sex education.
In January 2009, she spoke at the Planned Parenthood Presidential Inauguration Brunch in Washington, D. As announced in late 2009, Walsh partnered with the ocean conservancy and advocacy group Oceana to call for increased sea turtle protections.
As of 2017, Walsh starred in the 2017 Netflix drama series 13 Reasons Why as the mother of a child who committed suicide.
Her performance was dubbed to be the "best work" of her career and was met with critical acclaim.
Before modeling, Walsh worked at Burger King and Dairy Queen.