Dressed in a black frock-coat, wing-collared white shirt, black floppy ribbon tie, cream and brown checked trousers and waistcoat, the first incarnation of the Doctor is distinctive enough before even considering his lined, hawklike face, penetratingly intelligent blue eyes and long, swept-back white hair. He is undoubtedly an eccentric, but a particularly clever one.

In this incarnation, the Doctor is tetchy and temperamental: one moment he can be warm and friendly, the next he can be accusing his companions of all kinds of treachery. He is vain, arrogant and determined to get his own way, no matter what arguments are raised against him. As far as the Doctor is concerned, he knows best and everyone had better do it his way. When he displays his bloody-mindedness, the Doctor becomes an alarmingly aggressive figure: if he loses an argument he becomes ruffled and unsettled.

At the same time, his strong mind and ability to think quickly make him an inspiring leader who can restore courage to his frightened companions or direct people who are lost in indecision. His charm can equally be turned on powerful leaders to gain their favour. Yet beneath the charm he can be a devious schemer. He maintains his clear-headedness by abstaining from alcohol.

Virtually all the Doctor's new acquaintances are mistrusted when they travel in the TARDIS and it takes time for the Doctor to treat them as friends. He regards all of them as largely ignorant of science and short of ideas, but will quickly assume the credit for any of his companions' cleverness. His memory for names is poor, and he will often confuse them: Ian Chesterton often gets called Chesterfield, for instance.

On his travels the Doctor will talk little of his home planet, from which he is a runaway. To all intents and purposes he is a gentleman time-traveller with a limited ability to control his ship. For all his seeming intelligence and capabilities, the Doctor is sometimes just bluff and bluster. He is somewhat amoral, making his own, sometimes erroneous judgments on good and evil.