From a long list of the series' departing characters, perhaps Jackson Avery and Alex Karev best demonstrate the extremes of how Grey's Anatomy handles its exiting cast members. Few shows have had a healthier runtime than the Shonda Rhimes created hit medical drama, but with longevity comes inevitable cast turnover, and some exits are simply more graceful than others.
The most recent departure came in the form of Jesse Williams' Dr. Jackson Avery, who had been a regular presence on the show since season 6. While other mainstays like Ellen Pompeo, Chandra Wilson, and James Pinkens Jr. extended their contracts to continue on in Grey's Anatomy season 18, Williams opted out of returning. However, the show's writers (led by showrunner Krista Vernoff) managed to craft a well-played swan song for Jackson Avery, who decided to move to Boston to take over the Catherine Fox Foundation, aiming to tackle a healthcare system that disproportionately slights people of color.
In retrospect, Grey's Anatomy seemed to have been setting up Jackson's departure for quite some time now. Throughout the series, the prodigious plastic surgeon had been branded something of a wandering spirit, unable to find contentment in both his role at the hospital and in his personal life. Recently, much of Jackson Avery's story had been wrapped up in his desire to reclaim his tarnished family name, using his extraordinary wealth to help better a world he sees as broken. Grey's Anatomy season 17 has not shied away from the health care system's inequalities, now exacerbated by a global pandemic, and smartly connects these real-world issues to Jackson's motivations for leaving. The writing decision ultimately gives the character a noble, satisfying conclusion. Unfortunately, the same cannot be said for Karev's ending, which felt odd and unearned after actor Justin Chambers' sudden departure.
While Chamber's decision to leave the show after so many years was understandable (he was a major player since Grey's Antatomy's pilot episode), Alex Karev left some narrative collateral damage in his wake, especially as it related to Jo Wilson. Shortly before Chamber's departure, Alex and Jo were finally married. When Jo's struggles with mental health became evident, Alex reaffirmed his love and commitment to her, showing a hard-won maturity that fans had been waiting for. So, when Alex abruptly left Jo (explaining in clunky voiceover that when he learned that his ex-wife Izzie secretly had his kids and he now wants to be with them), much of that growth almost immediately dissolved, leaving behind an impression that Karev never really evolved beyond his "Evil Spawn" persona.
Perhaps the key to a successful conclusion for any television character has everything to do with timing. Many of Grey's Anatomy's most effective exits had a bit of runway to work with, such as the run-up to Cristina Yang's/Sandra Oh's tidy conclusion in season 10. This approach allows for the tying off of loose ends and for viewers to witness final scenes with the departing character and the people they are leaving behind who shaped them along the way. Of course, Grey's Anatomy has found other, far more definitive ways of handling expired actor contracts–just ask Derek Shepherd, George O'Malley, Lexie Grey, Mark Sloan, Adele Webber, and the many other characters who were killed off in the writers' room.
Thankfully, both Avery and Karev made it out of Grey's Anatomy with their lives, leaving the door open, however narrowly, for the characters to make one last trip to Grey-Sloan Memorial before the inevitable series finale. A return for Jackson wouldn't feel out of place considering where he left things. But if Alex were to swing by for a final visit, things could get a little awkward thanks to the way he was written out of the show.