Peter Cushing is the first (and only) 'Dr. Who'. But he's not the first Doctor, because the movies which he starred in, while based on Terry Nation's first two Dalek serials, were never meant to be considered part of the same universe as the TV show.
And of course the movies were made after the TV series began, so even if Dr. Who and the Doctor were the same character in the same franchise (which they aren't), he wouldn't have been the first.
Meanwhile, you could describe Cushing's character an "alternate-universe First Doctor" or something like that if you wanted to, just like Geoffrey Bayldon's character in the first Doctor Who Unbound audio play. So, if you make a list of all of the Doctors including alternate/potential/etc. Ones (including the Valeyard, the Curse of Fatal Death and Shalka Doctors, the various Unbound Doctors, etc.), Cushing would be the second one on the list, but if you make a list of the 11 "real" Doctors, Cushing won't appear.
- ↑ Cushing himself suggested, a few years later, that maybe his character was a future incarnation of the Doctor being forced to relive his early adventures for some reason. But none of the writers of the TV show or other media have taken that seriously—in fact, they've been more interested in explaining how the movies could exist as movies in the Whoniverse, than explaining how Dr. Who could exist as a real person there.
- ↑ Even that list might have 12 or more people: Richard Hurndall played the "real" First Doctor in The Five Doctors, after Hartnell's death. Jon Culshaw played the "real" Fourth Doctor in the audio play The Kingmaker when Tom Baker decided not to do it, and since then the other early Doctors have been played by other actors in audio. The Eleventh Doctor was even briefly played by Daniel Anthony in Death of the Doctor. But Cushing won't be on it.