Doctor Who: Every Version Of The Doctor Explained
21. The Fourth Doctor (First Appearance: 1974)
After his regeneration, the Fourth Doctor set off in the TARDIS to explore all of time and space once more.
A bohemian wanderer, the Fourth Doctor never stayed in one place for too long, despite having more seasons under his scarf than any other Doctor. He had a wittiness and a wildness about him not seen in previous Doctors, traits that have remained – even slightly – in every subsequent incarnation.
Highlights of the Fourth Doctor's time in the TARDIS include his ascension to the position of Lord President of Gallifrey (he didn't last long), some proper fleshing-out of Gallifrey and the Time Lords, and inadvertently burning the real Mona Lisa.
After many years of adventuring, the Fourth Doctor regenerated after falling from the Pharos radio telescope, thanks to the machinations of the Master. As he died, he merged with a mysterious manifestation of himself known as the Watcher – a creature about which we still know very little – creating his next incarnation.