This Doctor was created on Earth in Exeter in 4132 when his Tenth incarnation was stabbed through the gut by the Ultimo Creature and regenerated While Christy Johnson watched on. He then took her with him ("The Ultimo Factor").
The Doctor and Christy had numerous adventures, doing battle with vampires, Daleks, Cybermen, zombies and the Master ("Night of the count"; "Daleks in the big city", "Return of the Daleks"; "Steel Head, Steel Heart"; "Dead men walking"; "End of everything"). However, it was when they met the Master that she was lost when she took a shot from his Temporal Disruptor, erasing her from time and space, with only the Doctor, the Master and Captain Jack remembering she ever existed ("End of everything").
Following this, the Doctor travelled alone for a while. He battled cybermen and an army of autons during this time, as well as travelling to Camelot and meeting Sir Lancelot ("War of the Cybermen"; "Plastic shouldn't be in so much"; "Knights of the round table").
After that period, the Doctor met a new companion, Lucy, and together they defeated Davros and his army of Daleks ("New friends and old enemies"). They travelled together for a short time, with her only being present for two adventures but meeting the Ood and the Karashvians ("Attack of the ood"; "Invasion of Karashvios"), with the latter having their planet invaded by Cybermen. The Doctor then took her back home ("Invasion of Karashvios").
Literally within minutes of landing at his next destination, the Doctor met a new companion, Tara. She helped him defeat a rampaging weevil by use of a temporal replacement field ("Flesh eating monster").
However, that was one of her only two adventures with this Doctor. On their second adventure, they met the Daleks. The Doctor fought valiantly and was able to stop them. However, just as the final Dalek was being destroyed, it fired a blast at the Doctor. This blast passed through the Doctor's stomach and hit the TARDIS console, causing damage. He then regenerated into his next incarnation ("Dalek Wars"; "Regeneration").
However, this was not his last appearance. He appeared one more time, albeit in his mind, to his twelth incarnation during his regeneration into his thirteenth incarnation ("Regenerated").
This Doctor's dress sense was quite unique. He wore a olive green sherlock holmes style suit with smart brown shoes ("Night of the Count"; "Dalek Wars"; "Regeneration"; "Regenerated"). He also on occasion wore the brown coat his previous incarnation had worn, but only when he deemed it "too cold" ("Dead men walking"; "Invasion of Karashvios").