
Kate Walsh Is Coming Back to 'Grey’s Anatomy' — but Why Did She Leave in the First Place?
With Season 18 premiering and Dr. Addison Montgomery coming back, fans are asking: Why did Kate Walsh leave ‘Grey’s Anatomy’ in the first place?

Sep. 30 2021, Published 7:03 p.m. ET
ABC’s medical drama show Grey’s Anatomy has been on-air for a long time, and as it enters into its 18th season, we’re sure to have a few surprises thrown in. One that we already know about is the return of Dr. Addison Montgomery, played by Kate Walsh.
Fans are thrilled and excited for her return. The storyline and drama she brought to the show was loved by fans. But why did Kate Walsh leave Grey’s Anatomy after Season 3? Here’s what we know.

Why did Kate Walsh leave ‘Grey’s Anatomy’?
Kate Walsh made her first appearance during Season 1 of Grey’s Anatomy as Dr. Addison Montgomery. Though initially she wasn’t a main character, she came into the scene with a dramatic bang. Making a surprise visit to Seattle Grace Hospital, Addison arrived and stirred up the pot.
Addison was Dr. Derek “McDreamy” Shepherd’s ex-wife. And at the time, we know Meredith Grey, the main character of the show, was madly in love with Derek. That caused drama, but there were some leftover issues between Derek and Addison, too, because it turned out she cheated on Derek with his best friend, leading to their split.
Fans were excited about the drama. It added some interesting twists to the romance storylines. And it helped that Addison herself was a kick-butt doctor. It wasn’t a surprise to fans when Kate Walsh became a series regular in Season 2, reprising her role as Dr. Montgomery, but with so much more screen time.
According to IMDb, Kate played Dr. Montgomery in 59 episodes, spanning the years between 2005 and 2012. With such a smashing success playing the character who was well received, why did Kate Walsh leave the show so early on in its run after Season 3?
For her own spinoff show, of course! The character was such a hit that Kate was offered the lead role in a Grey’s Anatomy spinoff, also from Grey's creator Shonda Rhimes, titled Private Practice. Kate took the same character to the new show and ran with it for several additional seasons.
Private Practice, which followed Addison as she restarted her career in Los Angeles, premiered on ABC in September 2007. In that show, Addison left Seattle and worked at a private clinic that two of her friends started.
Private Practice came to an end in 2013, after seven years and six seasons, finishing its run in January 2013. The final episode was Addison’s wedding day where she married fellow doctor Dr. Jake Reilly, who worked at the same medical practice.
Now, years later, Addison is set to return to the latest season of ‘Grey’s Anatomy.’
It’s been reported and confirmed that Kate Walsh is reprising her role of Dr. Addison Montgomery for Season 18 of Grey’s Anatomy. It’s huge news for fans of the medical show and the spinoff.
No one knows yet what the storyline will be or what it is in the story that brings her back to Seattle. We also don’t know how many episodes we can expect to see her in again. IMDb gives a little hint on its episode listing that seems like we’ll get at least three new episodes with Kate, but the rest we will just have to wait and see.
Season 18 of Grey’s Anatomy premieres on Sept. 30, 2021, at 9 p.m. ET on ABC.