Currently the Doctor is in his 11th regeneration played by the actor Matt Smith. After a long hiatus the series began again in 2005 starting with Christopher Ecelsten playing the 9th regeneration. His actor lasted a single season until regenerating and becoming the 10th regeneration played by David Tennant. After 3 seasons of running through time and space Matt Smith took the reins.The Doctors actors from left to right are William Hartnell, Patrick Troughton, Jon Pertwee, Tom Baker, Peter Davison, Colin Baker, Sylvester McCoy, Paul McGann, Christopher Eccelston, David Tennant and Matt Smith