The Real Reason These Actors Left Doctor Who

When it debuted in 1963, "Doctor Who" was seen as an educational adventure show for kids, but quickly grew to become a cultural landmark in the U.K. Uniquely British, it captivated millions in its native England before global audiences ever got a taste of the phenomenon. Unlike so many of its short-lived sci-fi contemporaries like "Star Trek" or "Lost in Space," the little time-hopping family series called "Doctor Who" endured, ultimately running an astonishing 26 seasons before it came to a close in 1989. 

In 2005, the show returned and has been running ever since, with a new cast once every few years. While The Doctor's faithful companions have come and gone, The Doctor has merely regenerated, allowing the character to be played by no less than 14 actors in total — and that's not counting actors like John Hurt and Jo Martin who played The Doctor, but not in the capacity of an official series lead. But the reasons stars leave the series can vary wildly. For some, it might be a simple matter of aging out of the role or growing weary of the weekly grind of filming. For others, it might be because of a behind-the-scenes controversy or an unhappy producer who forced them out.

But in the history of "Doctor Who" some of the biggest stars have walked away to the shock of many fans. Now, we're digging into cast interviews to discover why they really left the show.

Arguably, the most beloved of The Doctor's many companions over the years might still be Sarah Jane Smith, played by actor Elisabeth Sladen. She joined the show in 1973 as a sidekick to Jon Pertwee's Third Doctor and continued after the arrival of Tom Baker's Fourth Doctor. She remained partway through the show's 14th season, departing at the conclusion of "The Hand of Fear" in 1976. It was that year that Sladen decided it was time to leave, feeling she should go out before fans grew tired of her.

In her autobiography, Sladen talked about how concerned she was that she'd be pushed out of the show following a change in producers. "When I go, it's going to be my decision," she recalled thinking. "It's going to be when Sarah Jane Smith is still popular — I'm not going to be pushed." Nevertheless, Sladen stuck with the show a little longer, but she knew when to move on. "You know when the time is right. You can't stick around just for the money." 

But Sladen also hoped that Sarah Jane wouldn't be killed or married off. Her exit was written in such a way that she was able to return for the 2006 episode "School Reunion" before getting her own spin-off, "The Sarah Jane Adventures."

In 2010, "Doctor Who" got an overhaul, bringing in Matt Smith as The Eleventh Doctor and Karen Gillan as his new companion Amy Pond. Arthur Darvill played Amy's boyfriend Rory, and he'd join the cast as a series regular a year later.  Midway through their third year on the show, though, Gillan and Darvill shocked fans when they left the show, with The Doctor losing Amy and Rory in the episode "The Angels Take Manhattan." 

At the time, both actors' careers were on the upswing, and Gillan told IGN in 2012 that she knew she had to leave the show. "I wanted to make sure that I went on a high when the character was at her prime. ... It just felt right. I like to go on instinct." But it wasn't just Gillan, because Darvill was also ready to go. In 2023, he talked about how their ending came about in an interview with Rob Brydon. 

"We all had a meeting, they said 'how long do you want to do [this]... this is what we think,'" he recalled. "And myself and Karen kind of felt the same, and they wrote us a good ending and we left." A year later, Gillan joined the MCU as Nebula, while Darvill was cast alongside David Tennant in the critically acclaimed crime drama "Broadchurch."

The era of Colin Baker, who joined the show in 1984, is sadly marked by the beginning of the end for classic "Doctor Who." A confluence of factors led to its decline, including a string of bad stories, lower production values, and the general perception of the show as goofy and childish. Still, nobody can fault Baker, who brought a touch of cynical charm to the role that it hadn't had in years. But Baker's era also produced shorter seasons, with less than half as many episodes as in previous years.

Regrettably, Baker didn't leave "Doctor Who" by his own choice. Mostly due to the troubles the show was facing, producer John Nathan-Turner was under pressure to improve the show and chose to make Baker his first major move, essentially firing the actor by phone call. This was particularly troubling for the actor, who was expecting a baby, but he kept a solid perspective, seeing it instead as paternity leave. But that doesn't mean Baker was happy: On the contrary, when asked to return for the next season's premiere to film his own death and regeneration into Sylvester McCoy, the actor outright refused.

Years later, Baker would express regret for taking his bitterness out on the fans, effectively denying them a goodbye. "I was being brutally selfish at the time and I just felt annoyed," he told Radio Times. "Because I loved that part ... and I thought I had more to offer."

By 1996, "Doctor Who" had been off the air for seven years, but there was interest in bringing the franchise to a new American audience. A co-production with 20th Century Fox — at one point intended to be directed by Steven Spielberg — did just that, but despite its American backing, British star Paul McGann was picked for the main role. The movie reintroduced The Doctor for a new generation and overhauled the series. Though it's not especially well-known or highly regarded, even among devoted "Doctor Who" fans, the 1996 movie had an enormous impact on the franchise.

From the steampunk look of the TARDIS to the possibility of The Doctor being romantically linked to his companion — not to mention its more fast-paced opening credits sequence — the later 2005 reboot of "Doctor Who" took a lot of inspiration from the 1996 telefilm. Unfortunately, while ratings were solid in the U.K., it was a flop stateside. As a result, Fox — which bankrolled the project with the hopes of spinning it off into a new weekly series — balked at supporting a follow-up. 

About a decade later, when BBC renewed the franchise on the small screen, McGann wasn't asked back, making McGann's time as The Doctor one of the shortest yet. But fans never forget a Doctor and McGann made a surprise return for "The Night of The Doctor" in 2013.

When a doctor regenerates and a new actor arrives in the role, it often means there's a new companion on the horizon, too. So, flash back to 1974, and the series was in need of a new lead after Jon Pertwee left. In came Tom Baker, with his long scarf and broad smile, and with him was new assistant — Harry Sullivan, played by actor Ian Marter, who'd appeared as a different character a year earlier and obviously impressed producers.

The duo proved delightful, but Harry wasn't long for the series, leaving after just two serials into his second year. And the reason might be somewhat surprising, with its roots in the exit of Jon Pertwee when they were still searching for a replacement. "They cast me (as Harry) before they knew anything about the new Doctor," Marter told Doctor Who Magazine in 1984. "I was brought in in case The Doctor had been made much older and couldn't handle the physical side of the series. ... As it was, Tom didn't really need me there at all."

Though producers tried turning him into something of a comic relief character, they eventually felt that it wasn't working. "I hadn't decided to go. Harry, the character (and that meant me too), was dropped from the series because he had finally outlived his usefulness and was simply getting in the way."

With Amy and Rory out in the middle of Season 7, The Eleventh Doctor needed a new companion. Jenna Coleman appeared first in the 2012 episode "Asylum of the Daleks," in a rare case of producers teasing her future arrival, which came properly several episodes later. Eventually, as companion Clara Oswald, she became the center of a seasons-long story that ties back to the origins of The Doctor himself. And when Matt Smith left the series, Coleman transferred her services to The Twelfth Doctor, Peter Capaldi, eventually becoming the longest-serving companion on the relaunched series.

To the surprise of many, Coleman left after Season 9's "Hell Bent" when Capaldi still had another year to go on the show. Believe it or not, though, she almost left earlier. "My contract was up at the end of [Season 8]," she told Entertainment Weekly. "That initiated conversations of, 'Okay, when and how [do you want to leave]?' ... There were just ongoing discussions about how to end Clara's story, as it were, in the TARDIS, and this is where it ended up."

As for why she didn't simply renew her contract, well, she reportedly walked away because she'd snagged the leading role in the critically acclaimed drama "Victoria."