How Every Doctor Who Got Cast

In 1981, Doctor Who producer John Nathan-Turner was grappling with how to replace Tom Baker. It was the biggest challenge for the show since his predecessors had to seek out potential candidates for the Second Doctor.

JNT approached Richard Griffiths (these days best known as Uncle Vernon in Harry Potter) about the role, but he wasn't available.

An actor who was available, despite simultaneously appearing in two sitcoms (Holding the Fort and Sink or Swim) was Peter Davison.

JNT had worked with Davison before on All Creatures Great and Small, the show that had made Davison a household name. Davison's profile and his youthful appearance were deemed a winning combination by JNT, who quickly offered the role to the initially reluctant star.

Davison worried about being too young to play the Doctor, and was also concerned about becoming typecast. He needn't have worried of course, as he would go on to become the most successful actor to have played the Doctor in the classic era. So much so that he's still working today, in shows like The Gold, Gentleman Jack, and Good Omens.