Doctor Who is the longest-running sci-fi show of all time, with over 60 years' worth of content since it first debuted. Even just counting the modern revival, the series has been going strong for nearly 20 years. Over that time, it has featured a lot of fantastic British actors in roles ranging from the titular Doctor to guest starring parts.
It is incredibly hard to determine which actors have been in the show the most, as the format has changed over the years. The first season, for example, included 42 half-hour episodes, while the newest season has only 8 hour-long episodes. Purely by episode count, the Classic Era stars blow the Modern stars out of the water. However, that tends to be a matter of structure, rather than prominence.
The actors cast as the Doctor and their companions in the revival have been in just as many stories as their Classic counterparts, which are easier to track with the episodic, rather than serial, format. Because of that, we'll focus on the modern era for this article, specifically looking at which stars have been in the most episodes there.
For those who are curious, the most prolific stars in the Classic Era were all actors for the Doctor, with Tom Baker in 173 episodes, William Hartnell in 139, and Jon Pertwee in 129. However, if you count by stories, rather than episodes, the sums are 41, 27, and 24, respectively.
In the modern era, the Doctor is still the most prominent role, with three of the six leading actors making it into the top five. However, there are also companions who have been in a large number of episodes, outlasting the shorter-lived Doctors. For the sake of clarity, we'll be skipping prolific voice actors like Nicholas Briggs and Jon Davey for this count, as they contributed to a wide variety of characters rather than being known for one.
With all of that said, it is time to dive into the top five Doctor Who stars in the modern era, by episode count. Which actors have fans seen the most, and how did they contribute to the show?
Karen Gillan
Karen Gillan played Amy Pond in series five through seven of the modern show, along with a brief appearance in Matt Smith's regeneration episode. She was the defining companion for the Eleventh Doctor, developing from a young girl who worshiped him to a brave companion, eventually ending up as his mother-in-law (two ways, if you dig deep enough).
She is also one of the many actresses who appeared in the show before making their debut as a companion. Karen Gillan was first cast in series four, where she played a Roman soothsayer in "The Fires of Pompeii." This gave her the unusual opportunity to star alongside future Doctor Peter Capaldi, neither of whom were playing the roles they would be most remembered for.
Technically speaking, Karen Gillan is tied with Billie Piper for the highest number of episodes, with each of the companion actors showing up in 35 episodes of Doctor Who. However, Karen gets the number five spot for her additional appearances, starring in two of the Night and the Doctor minisodes, all five Pond Life minisodes, and the special Doctor Who: Good as Gold.
Since her time on Doctor Who, Gillan has become best known for her role as Nebula in the MCU. This actually resulted in her being bald while filming her final Doctor Who appearance, wearing a wig made from her own cut hair. Ironically, Smith was wearing a wig thanks to his other roles as well. In 2024, Karen Gillan reunited with Steven Moffat and her on-screen daughter Alex Kingston in the mini-series Douglas Is Cancelled.
Jenna Coleman
Jenna Coleman played Clara Oswald in series seven through nine of Doctor Who, traveling alongside the Eleventh and Twelfth Doctors, as well as meeting the War Doctor and the Tenth Doctor in the 50th anniversary special. She was immediately drawn to the life of adventure that the Doctor offered, but she eventually established her own life as a school teacher.
However, Clara had an obsession of sorts with the Doctor, which led her to travel with him even when it was harmful to both of them. She jumped into his timeline, fragmenting her consciousness to protect his past from the Great Intelligence, which resulted in her appearances before her official companion debut. She also began acting like him, suffering when her own humanity proved more significant than her kinship with the Time Lord.
Altogether, Jenna Coleman was in 38 episodes, including her two and a half season arc and a brief appearance in Peter Capaldi's regeneration episode, "Twice Upon A Time." This makes her the companion with the highest number of episodes in the modern show's history. Since her exit from the show left Clara's story open, there is always the possibility that she will return in the future, either as her fragmented self or the version of her traveling with Me.
Since leaving Doctor Who, one of Coleman's most significant roles was as the titular queen in the series Victoria. This allowed her to show off a more regal side and break out of stereotypes she might have gained from being part of such an important show. More recently, she played Johanna Constantine in The Sandman, working with material by previous Doctor Who writer Neil Gaiman.
Peter Capaldi
Peter Capaldi has one of the most fascinating stories when it comes to his time on Doctor Who, because he plays three different roles throughout the franchise, with the most notable being the Twelfth Doctor. Taking over for series eight through ten, Capaldi’s version of the character was much more willing to confront his inner darkness than the earlier versions, which helped create some of the most interesting plotlines in the show's history.
In addition to playing the Twelfth Doctor, Capaldi played Caecilius, a Roman father seeking to save his family, in “The Fires of Pompeii” and John Frobisher, a civil servant caught up in the horrific events of the “Children of Earth” arc in Torchwood. While the latter is never explicitly addressed, the show does claim that the Doctor looks like Caecilius as a reminder to always try to save people.
As the Doctor, Capaldi was in 42 episodes of Doctor Who, along with an uncredited cameo in the 50th-anniversary episode “The Day of the Doctor,” an appearance in the 2016 spin-off Class, and multiple appearances in minisodes. Although this is a slightly smaller amount than some of the other lead actors, Capaldi’s time as the Doctor fits the standard three-season run that most actors have stuck to in the revival.
While most of the recent actors on Doctor Who have been fairly young when they took on their roles, Peter Capaldi was 56 years old in his first real episode as the Doctor. He had an established career, with his most prominent roles being Malcolm Tucker in The Thick Of It and Cardinal Richelieu in The Musketeers. After leaving Doctor Who, Capaldi joined the DC Universe as Thinker in The Suicide Squad and starred as Gideon Shepherd in the thriller series The Devil’s Hour.
Matt Smith
Matt Smith was the youngest actor ever to play the Doctor, portraying the Eleventh Doctor as a clever fool until someone was stupid enough to threaten the people he loved. His version of the character had a dark side, which was especially prominent in series 6, but he covered it up with a joyful (if sometimes manic) spirit and a passionate love for the companions he chose.
He had a difficult task, taking over for fan-favorite David Tennant alongside the first new showrunner since the show had been resurrected in 2005. However, he rose to the challenge and made fans fall in love with his version and his quirks, from bowties to fish fingers and custard. One of the most iconic elements of his time on the show was his relationship with River Song, one of the only romantic interests in the show’s history that seemed to stand on even footing with him.
In total, Matt Smith played the Doctor in 46 episodes of Doctor Who, although two of those appearances were part of regeneration episodes in other actors’ eras. He makes up for those minor appearances with at least 15 minisodes, a two-episode arc in The Sarah Jane Adventures, and a plethora of video game and documentary appearances thanks to being the headliner during the show’s 50th anniversary.
While Smith has frequently spoken about how much he loved his time on Doctor Who, he has sought out drastically different roles in the years since. He portrayed Prince Philip in the first two seasons of The Crown, Charles Manson in the bio-drama Charlie Says, and Milo in the 2022 film Morbius. Perhaps his best-known role outside of the sci-fi giant is as the mercurial Prince Daemon Targaryen in House of the Dragon.
David Tennant
To absolutely no one’s surprise, David Tennant is the star who has been in Doctor Who the most. Just counting his time as the Doctor, Tenant has been in 53 episodes of the series, primarily within series two through four. He played the Tenth Doctor, joining the show right when it found its new young audience.
The Tenth Doctor has consistently been a fan-favorite since he first debuted, with polls ranking him at or above the Classic Era favorite, Tom Baker. He was a snarky take on the character, capable of expressing deep emotions one minute and cracking jokes the next, providing a good balance between the angst of his predecessor and the goofy nature of his successor.
However, that is not all of the time David Tennant spent with Doctor Who. He was a massive fan from childhood, pursuing acting gigs related to the franchise even when it was not on the air. He voiced background characters in the 2003 audio specials Doctor Who Unbound and Doctor Who: Scream of the Shalka, along with four other podcast series.
Once he had taken on the lead, he had even more opportunities. He voiced the Doctor in the animated miniseries Totally Doctor Who, Doctor Who: The Infinite Quest, and Doctor Who: Dreamland. Tennant also appeared on-screen in two episodes of The Sarah Jane Adventures. He has continued returning for audio adventures with Big Finish ever since.
Even when his time was theoretically up, David Tennant continued to return to Doctor Who for its anniversaries. He appeared alongside Matt Smith and John Hurt in the 50th anniversary multi-doctor special “The Day of the Doctor” and reclaimed the mantle for the 60th anniversary specials. His run as the Fourteenth Doctor lasted for three episodes, with the opportunity to return in the future thanks to the new bi-generation process.
With so much Doctor Who in his background, it can be hard to remember just how many other worlds Tennant has played in. Along with taking on multiple animated roles (the most prominent of which is his portrayal of Scrooge McDuck) and making his way through every Shakespeare play, Tennant worked with future Doctor Who showrunner Chris Chibnall and future Doctor Jodie Whittaker in Broadchurch.
Like most of the other Doctor actors, David Tennant played a comic book villain as the repulsive Kilgrave in Jessica Jones, showing that he was capable of playing very different characters from the Doctor. Most recently, he starred in Good Omens alongside Michael Sheen and voiced Huyang in Ahsoka. Although he has had a remarkable career, there is never much doubt that Doctor Who will always be his home.