Kathleen Erin "Kate" Walsh is an American actress and businesswoman. Her roles include Dr. Addison Montgomery on the ABC television dramas Grey's Anatomy, Rebecca Wright on the NBC sitcom Bad Judge, Olivia Baker on the Netflix drama series 13 Reasons Why and The Handler in The Umbrella Academy.
Walsh has appeared in several other films, including Bewitched (with Nicole Kidman) and an "alternate film" to Anchorman titled, Wake Up, Ron Burgundy: The Lost Movie.
In 2003, Walsh appeared in Under the Tuscan Sun.
She has also starred alongside Dennis Quaid and Paul Bettany 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.