The role of Doctor Who is a cherished mantle that has been passed down through generations of actors, each bringing their own flair to the iconic Time Lord. As fans of the series, we often wonder why these talented individuals decide to step away from a role so beloved by audiences worldwide. Let’s explore the real reasons behind the departure of each actor who has brought life to the Doctor.
William Hartnell First Doctor
William Hartnell was the first to step into the Doctor’s shoes, setting a precedent with his departure due to health issues. Hartnell’s portrayal was influential, but as his health declined, it became necessary for him to leave, leading to the innovative concept of regeneration. 
Patrick Troughton Second Doctor
Patrick Troughton, the Second Doctor, faced the challenge of reinterpreting the role after Hartnell. Troughton’s naturalistic performance won admiration, but he was wary of typecasting. His decision to implement a ‘three-year rule’ has since influenced many successors in the role. 
Tom Baker Fourth Doctor
Tom Baker‘s seven-year tenure as the Fourth Doctor remains unrivaled. His decision to move on in 1981 was influenced by a desire for change after a long and impactful run. Baker’s life before becoming The Doctor was varied and challenging, which perhaps made his time on the show even more significant to him. 
Peter Davison Fifth Doctor
Peter Davison adhered to Troughton’s ‘three-year rule’ during his time as the Fifth Doctor. He recognized the perpetual nature of the role and chose to seek different opportunities while still at the peak of his tenure. 
Christopher Eccleston Ninth Doctor
Christopher Eccleston‘s time as the Ninth Doctor was brief but foundational for the modern era of Doctor Who. Behind-the-scenes tensions and creative differences played a significant role in his departure after just one season. My relationship with my three immediate superiors — the showrunner, the producer and co-producer — broke down irreparably during the first block of filming and it never recovered. They lost trust in me, and I lost faith and trust and belief in them,
Eccleston once explained about his exit. 
David Tennant Tenth Doctor
David Tennant, adored for his portrayal of the Tenth Doctor, left when showrunner Russell T Davies stepped down. Tennant expressed concerns about overstaying and felt it was time to move on despite being tempted by Steven Moffatt’s takeover. It would be very easy to cling on to the TARDIS console forever and I fear that if I don’t take a deep breath and make the decision to move on now, then I simply never will,
he shared during an ITV interview. 
Matt Smith Eleventh Doctor
Matt Smith, who took over from Tennant in 2010, brought a youthful energy to the Eleventh Doctor. His decision to leave was driven by a desire for new acting opportunities and personal growth. ‘Doctor Who’ has been the most brilliant experience for me as an actor and a bloke, and that largely is down to the cast, crew and fans of the show. I’m incredibly grateful,
Smith reflected on his departure.
Peter Capaldi Twelfth Doctor
The Twelfth Doctor, played by Peter Capaldi, cited an intense production schedule and a desire for change as reasons for leaving. Capaldi honored his predecessors like Hartnell and acknowledged that while his tenure might end, his connection with Doctor Who could continue through various projects if they met his standards for quality.