The series starts up with its original "old man Doctor", a gradnfatherly (if curmudgeony) older gentleman played by William Hartnell
Season 1
Season 2
Season 3
The Second Doctor
When William Hartnell elected to leave the show, taking its lead actor out of the running, the producers had to come up with a solution and quick. Their idea, which became an iconic part of the series: the Doctor regenerates on death into the next actor, Patrick Troughton.
Season 4
Season 5
Season 6
The Third Doctor
Jon Pertwee became the third man to play the Doctor, turning the character into a dapper man of action (as befit the spy serials common to the era).
Season 7
Season 8
Season 9
Season 10
Season 11
The Fourth Doctor
The most famous of the Doctors, Tom Baker took over the role and gave it the longest stint in history, seven years as the iconic, be-scarfed explorer.
Season 12
Season 13
Season 14
Season 15
Season 16
Season 17
Season 18
The Fifth Doctor
Peter Davidson's character was more indecisive, more boyish, taking a different turn from Tom Baker's role to remake the series for a new generation.
Season 19
Season 20
Season 21
The Sixth Doctor
The most hated of the Doctors, Colin Baker's turn as the character was abrasive and rough, a difference from the previous men that was too hard for audiences to take, and he was quickly pushed out of the show.
Season 22
Season 23
The Seventh Doctor
The final man to take on the role of the Doctor in the original run, Sylvester McCoy saw the series to its end, a whimsical but secretive character with more depth and interest than Colin Baker's turn.
Season 24
Season 25
Season 26
The Eighth Doctor
Leading the first attempt to relaunch the show, Paul McGann took over the role for a single TV movie that was supposed to launch the series in America, but failed to get much traction.
The lead actor for the sucessful relaunch, Christopher Eccleston's Ninth Doctor was troubled by the Time War that happened right before his regeneration, a dark time that he kept hidden (even if that darkness lurked behind his eyes).
With a new regeneration and a new face, much of the darkness of the Time War was able to be pushed further aside as the Doctor moved on with the amazing David Tennant at the helm.
Blending elements of David Tennant's Doctor with both the attitude of old and new, Matt Smith had a hard act to follow from the previous Doctor but he did an amazing job in the role.
Another Doctor that isn't as well liked among all the fans, Peter Capaldi's Doctor was meant to start off a new cycle of lives for the Doctor, so his turn was a riff on the original Doctor, making him more of a curmudgeon than the young explorers of the last few turns.
The first modern spin-off for Doctor Who, this series featured a more adult take on the franchise' trope as it followed a crew of alien crime hunters in Cardiff.
Thoughts on Russel T. Davies Returning to Doctor Who: With Chibnall and WHittaker leaving the series, the BBC is bringing back Russel T. Davies as show runner, and we take a moment to think about whether that's a good thing or not.