Initially this new Doctor was dazed and disorientated after collapsing outside his Tardis as he began his time in exile. When he recovered it soon became clear that the Doctor's third incarnation was as different again as the second from the first. Gone was the fool with the scruffy coat and in his place, a suave sophisticated individual with a taste for the finer things in life.

This Doctor never completely accepted his exile and made frequent, failed, attempts to break free. He was occasionally allowed to travel in his Tardis but only under the strict control of the Timelords. This led to him complaining of being a galactic yo-yo!

The Doctor had a flagrant disregard for the rules and regulations of society. Or rather he did have regard, so long as they didn't interfere with his agenda. However he wasn't slow to see how the United Nations Intelligence Taskforce - UNIT for short could benefit him as it had the resources he needed to try to break his exile. After agreeing to join UNIT as their scientific advisor, he found himself up against a variety of alien foes intent on conquering the Earth. This brought him into frequent contact with the head of the British arm of the Taskforce, Brigadier Alistair Gordon Lethbridge-Stewart. At first the Doctor was rather amused by the Brigadier's traditional military outlook,and would mock him for being as such. Despite their differences and occasional conflicts, the two built a firm friendship.

He was a very physical character having mastered the art of Venusian Aikido and was also a master swordsman. He'd trained in escapology, a skill that proved useful on a number of occasions. The Doctor had an affinity for various forms of fast transport, including a souped up vintage car, a hover boat and motorcycle amongst others and, as he progressed through his third incarnation, a series of events took place that were to result in profound changes to the Timelords and their earthbound prisoner.

An unexplained power drain placed the survival of the Timelords in jeopardy so they lifted the the Doctor's two former incarnations from their time streams, an action that violated one of their sacred laws. The Doctors successfully restored power to the Timelords and his third incarnation was rewarded with the lifting of his exile. He was a free man. No longer running in fear, no longer an exile. He was free to go where and when he pleased. Although he did travel to a number of times and places, the Doctor continued to act as UNIT's scientific advisor. It was clear that he was more settled and regarded the Earth as his home. Perhaps it was to do with his friendship with the Brigadier, but, whatever the reason, his travels through time and space were much less frequent.

After investigating a series of strange events at a Tibetan Monastery deep in the English countryside, the Doctor uncovered a plot by a group of intelligent spiders to rule the entire universe. He began a battle that ultimately led to the death of his third incarnation and the birth of his fourth.