Previous Doctor (Exile)

In a parallel universe, a version of the Doctor ran away from Gallifrey before his trial.

Biography
The Doctor attended the Academy with a Time Lord who found him to be "an eternal bore" and was annoyed when he stole a TARDIS and left Gallifrey. In an attempt to avoid capture he committed suicide, which in this version of reality caused the subsequent regeneration to change gender from the previous and which was considered a serious crime in Time Lord society.

This version of the Doctor later appeared to his subsequent incarnation as a hallucination in mirrors and other reflections which only she could see and hear, often chiding her for her poor life choices. (AUDIO: Exile)

Behind the scenes
This incarnation of the Doctor, played by Nicholas Briggs, was depicted on the cover art of Exile.