Grey’s Anatomy began its nineteenth season on October 6, 2022, but the main focus has been the setup for main star Ellen Pompeo’s expected exit. While the actor’s departure will be a big blow to the series, there might just be guest stars who can take up roles as part of the main cast if the past is any indication.

Quite a lot of the cast members began in a guest-starring capacity, ranging from Eric Dane’s turn as Mark Sloan to Caterina Scorsone’s upgrade after initially appearing as a guest actor from the show’s spin-off. It’s worth looking into how these actors started out with their characters and what propelled their roles into the main category.

Anthony Hill

Anthony Hill appeared in a guest capacity as a one-time love interest in a single season 16 episode, playing Winston Ndugu. Winston’s role was to create doubt in Maggie’s mind over being spontaneous with romance, although her relationship is left on ambiguous terms.

Hill was then promoted to a regular role starting from the next season, with Winston having moved to Seattle to be with Maggie. The character’s importance has changed from a guest appearance to Maggie’s husband, becoming part of the current crop of regulars.

Scott Speedman

It took Scoot Speedman three years before his guest appearance as Nick Marsh turned into a main role. The character appeared in season 14 as a patient at Grey Sloan Memorial whose life was saved by Meredith, planting the seeds for their later romance.

Nick resurfaced years later, this time pursuing Meredith for a real relationship that ended with the character getting a job at Grey Sloan Memorial. Speedman’s jump to a regular position is even more interesting considering that Meredith will be exiting the series while Nick is expected to remain.

Jason George

Jason George’s case is a special one since he started out in a recurring capacity before becoming a guest, which then morphed into a regular spot. The character Ben Warren was a love interest of Bailey’s in the sixth season until she broke up with him in the following season’s premiere.

George only had a guest role in Season 7 before leaving the show for more than a year. The actor returned in the eighth season, this time getting upgraded once more into a recurring capacity. It wasn’t until season 12 that George was promoted to the main cast, with five years having elapsed since he’d appeared as a guest star.

Chyler Leigh

Lexie quickly became a fan favorite Grey’s Anatomy character even if she was a little annoying, as her bubbly personality was hard to resist. She became a regular as soon as season 4 began, but Chyler Leigh’s first appearance in the series was as a guest star.

This took place in the final episode of the third season, where Leigh made her onscreen debut when Lexie introduced herself to George. Her guest appearance certainly packed a punch since the revelation that she was Meredith’s sister was big enough for her to be promoted starting from the next episode.

Kelly McCreary

Kelly McCreary had a similar entry into the series as Chyler Leigh did, arriving at the end of the tenth season before becoming a main cast member in the next. Maggie was introduced as Meredith’s long-lost sister, who arrived at Grey Sloan Memorial as one of the new doctors.

McCreary’s guest spot was intended to create a buzz since her character was not only another sibling of Meredith’s in Grey's Anatomy​ but was also the daughter of Richard Webber. McCreary didn’t have to wait long to be promoted to regular status, which she has held for about a decade now.

Kate Walsh

Kate Walsh had perhaps the most iconic guest appearance of any actor in the series, as Addison arrived in Grey’s Anatomy to ruin Meredith and Derek’s relationship. Her part was very brief, showing up in the final moments of the first season’s finale.

Addison’s reveal that she was Derek’s estranged wife rocked the series to its core, with such big-time information serving as a springboard for Walsh to be one of the main cast from the second season’s premiere. As far as major guest appearances go, Walsh is still unmatched in the impact she brought.

Eric Dane

Eric Dane was among the first actors to appear in one season and then be promoted to regular status in the next. Mark was hyped even before he showed up as the one who was responsible for breaking Addison and Derek’s marriage, ultimately appearing midway through the second season.

Dane had a memorable interaction with Patrick Dempsey and Kate Walsh’s characters, with this chemistry leading to the actor’s permanent role in the series. Dane stayed with Grey’s Anatomy for more than half a decade before bowing out in the ninth season with Mark’s demise.

Brooke Smith

Brooke Smith had an on-off role as Erica Hahn for two seasons until she became a mainstay in the fourth. Hahn appeared as a consulting doctor in Season 2, carrying the same role the year after that before she accepted a position at Seattle Grace.

Her character’s progression meant that Brooke Smith’s initial guest star status was upgraded to regular, with Hahn getting her own storylines with Sara Ramirez’s Callie. Unfortunately, the romance was negatively received by Grey’s Anatomy fans, with Smith written out of the show in season 5.

Caterina Scorsone

Caterina Scorsone is another actor who had a unique trajectory to becoming a main cast member. Scorsone was introduced in the spin-off Private Practice as a regular before appearing as a guest star in Grey’s Anatomy the same year when Amelia visited her brother.

Scorsone returned to the main series after Private Practice’s conclusion, initially reprising her guest role until Amelia became a permanent fixture in Meredith’s life. Scorsone’s crossover between Private Practice and Grey’s Anatomy proved fruitful since she’s been playing the part for well over a decade by now.

Kevin McKidd

Unlike most of his other castmates, Kevin McKidd became a regular in the same season that he was introduced as a guest star. Owen Hunt showed up in the premiere of the fifth season, where romantic sparks with Sandra Oh’s Cristina Yang were well-received.

McKidd’s character had taken off following his debut, only to return as part of the hospital’s new staff several episodes later. McKidd stands as a prime example of how making an impact as a guest performer can quickly lead to a greater role, with the actor now one of the longest-running stars in the series after more than 14 years.

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