 The Ninth Doctor is an incarnation of the Doctor , the protagonist of the BBC science fiction television programme Doctor Who . He is portrayed by Christopher Eccleston during the first series of the show 's revival in 2005 . Within the programme 's narrative , the Doctor is a time travelling , humanoid alien from a race known as the Time Lords . When the Doctor is critically injured , he can regenerate his body but in doing so gains a new physical appearance and with it , a distinct new personality . 
