Seventh Doctor

Regeneration - Post-Regeneration
It has been suggested (mostly through journeys through the Doctor's psyche) that his seventh self forced a regeneration in his sixth persona because he was too out of control, and was heading down the road to become the Valeyard. (NA: Timewyrm: Revelation)

Thus when the TARDIS was attacked by the Rani, the Doctor deliberately hit his head on the console, triggering a regeneration and allowing his seventh persona to come into being.

Following his regeneration he had a slightly comic personality, due mostly to post-regenerative trauma.

Ace and Facing Fears
When the Doctor and Mel arrived on the planet Svartos the Doctor encountered Ace, a much more brash human and recognised something in her that would assist him in the future as Time's Champion. He used a mild form of hypnosis to persuade his current companion Melanie Bush into leaving him. (NA: Damaged Goods)

The Doctor lead Ace to through many challenges, leading her to face her fears, with the intent that she might take his place in the future.

Time's Champion
The Doctor became the eternal Time's champion, assisting the universe and Time in the more complicated and hard of historical challenges. One such challenge involving the Hoothi was seen by Ace as an ultimate betrayal, leading her to leave his company during events on the planet Heaven, it also lead Bernice Summerfield to join him. (NA: Love and War)

Characteristics
The Seventh Doctor was a darker character, manipulative and frequently saw the 'bigger picture' rather than the world before him.

Personality
to be added

Habits and Quirks
The Seventh Doctor played a lot of chess, and not just on a chess board. He used it to battle his enemies and also to move his companions and his adventures around in the universe. (DW: The Curse of Fenric) He's also famous for his "rolling r's".

Mysteries and Discrepancies
The Doctor made a slip of the tongue when discussing the Hand of Omega with Ace in 1963, stating that 'we' had trouble with the prototype, rather than 'they' being early Time Lords. He may have been referring 'we' as a species not 'we' as a group.

Lady Peinforte claimed knowledge of the Doctor's actions during the 'Dark Times' of early Gallifrey, well before his assumed birth date, gathered from the Silver Nemesis statue.

The Doctor once stated to Davros that he was 'far more than just another Time Lord'.

Key Life Events

 * The Doctor regenerates. (DW: Time and the Rani)
 * First meeting of Ace and the Doctor on Svartos. (DW: Dragonfire)
 * The Doctor begins to show a darker side of his personality when he gives the Hand of Omega to Davros in order to ensure the destruction of the planet Skaro. (DW: Remembrance of the Daleks)
 * The Doctor discovers the Master on the Cheetah World (DW: Survival'')
 * The Doctor first meets of Professor Bernice Summerfield and Ace leaves him. (NA: Love and War)
 * Loss of his TARDIS. He takes an alternative timeline TARDIS left by his third self who, in this universe, has died. (NA: Blood Heat)
 * The Doctor defeats Mortimus. (NA: No Future)
 * Ace departs a second time, becoming 'Time's Vigilante' in order to watch over Earth for him. (NA: Set Piece)
 * The Doctor changes into a Human. (NA: Human Nature)
 * Settling old family business, the Doctor returns to the House of Lungbarrow on Gallifrey. (NA: Lungbarrow)
 * The Doctor regenerates into his eighth incarnation. (DW: Doctor Who: The TV Movie)