'Grey's Anatomy': Kelly McCreary on Maggie's Full-Circle Goodbye and Those Surprise Cameos (Exclusive)

The longtime star breaks down her final episodes and why she was 'thrilled' to see two familiar faces return to send her off.

Spoiler alert! Do not proceed if you have not watched Thursday's two-hour episode of Grey's Anatomy.

Maggie Pierce is off to new adventures. Grey's Anatomy said goodbye to longtime star Kelly McCreary on Thursday's two-hour farewell episode, which marked the actress' final appearance as a full-time series regular.

Though Maggie jetted off to Chicago to begin her new life and job, she had several loose ends to tie up with regards to her crumbling marriage to Winston (Anthony Hill) and whether or not to stay in Seattle to work on their relationship. After a brief rekindling of their romance, Maggie and Winston faced the brutal reality that they were two people who were on very different paths. And one of Maggie's biggest worries, and a legitimate one, staying for the sake of a relationship that was likely on its last legs, giving up her passion -- her work -- and having regrets about it later.

"We did the best we could," Maggie tells Winston during the former couple's difficult conversation about their marriage being over. "Neither of us is to blame... I love you, but I have to go."

Of course, McCreary's goodbye wouldn't be complete without surprise appearances by Kate Burton, who returned as Maggie's biological mother Ellis Grey, and LaTanya Richardson Jackson, who reprised her role as Maggie's adoptive mom Diane Pierce, in the episode-ending elevator scene. After Maggie shared a sweet "see you later" moment with Richard Webber (James Pickens Jr.) and was gifted a replica of a mini park bench -- commemorating the moment Richard found out he had a daughter -- she entered the Grey Sloan elevators one last time, but she wasn't alone. Beside her on either side were Ellis and Diane, and after Maggie got off the elevator to start her new life, they both smiled at each other as they symbolically sent her off.

"It's obviously bittersweet. It's nine years of life, nine years of living with this character and my Grey's Anatomy family. It's hard to go, but at the same time, it feels like the right thing creatively and for my life. So it's all of the things, it's all of the emotions," McCreary told ET of her Grey's goodbye, who spent nearly a decade on the ABC medical drama.

"I've had these amazing opportunities to play out some really terrific storylines -- hard and painful and hilarious, all of it," she continued. "It's pretty wild to look back, and in my last week or two of shooting those last couple of episodes, I would arrive on the set and have flashbacks to my earliest scenes on those sets. And these are memories I haven't had in years in some cases, but I would think of people who haven't been on the show in forever. But then I'd look around and so many people in the room were still there. It was really a trippy experience, very visceral experience of remembering how different I was then, how different Maggie was and how much has changed for both of us in the space of nine years."

But this won't be the last time Grey's fans will be seeing McCreary donning the white coat, as she'll be appearing once more. To break down her final episodes as a series regular, McCreary spoke to ET over Zoom about her feelings over Maggie's send-off, why she was "thrilled" to have Burton and Jackson back and her upcoming Grey's return in the season 19 finale.

ET: Up until this point, Maggie had been juggling quite a lot in her professional and personal life, and at the end, Maggie seemed content with where she was going. Was this the ending that you envisioned for her?

Kelly McCreary: Yeah. One of the anchoring elements of this character is that she was adopted and came to find out more about her mother, and doing so she found even more family and then built her life there. But the question was always there of, "Who am I? How did I get to be this way?" Obviously she has had so much love poured into her by her adoptive parents in Boston, but at the same time, I think... Listen, Maggie and I are the same age. I'm in a place in my life too -- and I'm a mom now too, right? I'm reflecting a lot on how I was poured into and how I elevate myself, given the tools that I had. What did my parents give me and how do I do one better for the next generation? I think that Maggie now has a good idea of how those two moms poured into her and what tools they gave her. And now she's setting off for their legacy. That I love, that it turns into a legacy story in the end. So, the very long answer to your question is, I loved how that turned out because it really closes the circle on the question of why she came in the first place.

Eric McCandless/ABC

You mentioned Ellis and Diane. Kate Burton and LaTanya Richardson Jackson returned for that last scene in the elevator, seemingly sending her off. What did that final scene mean for you? 

I loved it. I thought that was an absolute stroke of genius. Another one from [showrunner] Krista [Vernoff]. And I thought that was so beautiful because I think they would be proud of her. I think that that really, really matters to her -- to make her mothers proud, to stay connected to their memory and to their legacy. She's been visited by their ghosts on more than one occasion. They figure very prominently in how she views the world and how she moves through the world. So it was so great to have them come back. I couldn't believe they were both available and wanted to! I was so thrilled. It was a wonderful fun day of shooting.

I had actually done a play with Kate Burton shortly after she shot the pilot of Grey's, like a hundred years ago. So I've known her a really long time. And LaTanya and I really bonded when she came on to play Diane, Maggie's mom, and she too -- both of them have been wonderful mentors and nurturing figures in my life personally. So it was a very special for Maggie and it was special for me to have them.

Maggie and Winston's conversation about why they needed to part ways and end their marriage was a difficult one, but felt very real and very mature about the reality of where they are in their lives. Was this the end of that relationship for you or do you still see a future for them?

Well, I think as you said, the door remains open because they did handle it in a mature and respectful way. And I think that for all of Maggie's relationship and challenges over the last nine seasons, that's where we see her growth. You don't have to detonate it on your way out and you can make sure that the love is there and that it's felt and that the respect is there and that misunderstandings have been cleared and that there is a very clear understanding of difference. She's not always been great at communicating that. So it was beautiful to see and to play her doing better this time because that is what you try to do in life is when you know better, you do better. Even then you can still know and not do better. I felt very lucky that I got to play her doing better.

Even though you're saying goodbye to Seattle, you're returning for an episode before the season is over. What can you share?

Yes. Maggie will appear in the finale. We just had the table read yesterday. It was so wonderful. First in-person table read since pre-pandemic. It was great.

What brings her back into the fray? And what was that like to just be back and see everybody again?

I don't think I can tell you too much about what brings her back, but it is medically-related. And oh my God, it was amazing to be back. I love those people. First of all, I've been back almost weekly to do ADR and so I feel so lucky that I've been able to have a very slow... What's the word? I keep thinking of Velcro and how Velcro separates really slowly. [It's been] very nice. It's been gentle on me and I've been able to really take my time saying goodbye, which is another beautiful thing that the writers created for Maggie this season, were all of these opportunities to really sit down or have face-to-face connections and say goodbye, have some closure with her closest loved ones -- Richard, Winston, Amelia, even Meredith before she left. It's been nice to be able to have a slow burn on my departure and then being able to go back for a table read was so joyous and celebratory. There is just nothing like being in the room altogether at the same time. We haven't done that in a really long time and it's magical.

How do you think Maggie will do in Chicago and in her new gig? I'm sure she'll thrive, but curious what you think...

I think that she's probably doing great. I think she was really ready for a change. And this is actually going to be the first time she's ever lived alone. She's really going to like that. She's never had that experience. This woman, she went from her family's house to Meredith's house to her living with her husband, and I think she's going to be getting it and living her best life.

What will you take away most from your time on Grey's?

I'm going to take away the hope that I was able to give as much to as many people there as I was given from that place. It was an incredible opportunity. I got to do some really fun, really hard, creative work. And I met my husband and had a baby, and I had a lot of wonderful life there. I hope that my impact on that place was as positive as it was on me.

Grey's Anatomy airs Thursdays at 9 p.m. ET/PT on ABC.