The Sixth Doctor is the name used for the sixth incarnation of the Doctor. He set himself apart from the other incarnations because of his brightly colored clothes and brash personality.
After his regeneration (this going from the Fifth Doctor to the Sixth) he was so confused that he nearly strangled his companion, Peri. During his time he encountered many old enemies including The Master, the Daleks, the Cybermen, and the Sontarans. He also had an adventure with one of his former versions, the Second Doctor. He was later put on trial by his people, the Time Lords, and was prosecuted by The Valeyard, who turned out to be an evil future version of the Doctor. His regeneration into the Seventh Doctor occurred because of an attack by The Rani.
He also gave his age as 900 in one episode.
His personality was different from all the others because of his mood swings sometimes becoming violent, and being extremely egotistical. He was also very confident in his abilities and intolerable of fools, sometimes enduring Peri's company more than enjoying it.
He also had an affection for cats showed by his often wearing cat shaped pins on his lapels.