The Ninth Doctor is an incarnation of the Doctor, the protagonist of the BBC science fiction television series Doctor Who.

Christopher Eccleston plays him.

Within the series narrative, the Doctor is a centuries-old alien, a Time Lord from the planet Gallifrey, who travels in time in his TARDIS, frequently with companions. When the Doctor is critically injured, he can regenerate his body but gains a new physical appearance and with it, a distinct new personality.

Christopher Eccleston portrays the ninth such incarnation, a brooding and melancholic war survivor after a Time War in which he wiped out both his race and the enemy Daleks. His first companion is Rose (Billie Piper), whom he plucks from obscurity on the planet Earth and to whom he grows increasingly attached.

The 9th Doctor also travels briefly with unruly boy-genius Adam (Bruno Langley) and with a 51st-century con man and former ‘Time Agent’ Captain Jack Harkness (John Barrowman). Source – Wikipedia

Nice to meet you, Rose. Now run for you life!

9th Doctor