The First Doctor is the original incarnation of the Doctor, the protagonist of the British science fiction television series Doctor Who. He was portrayed by actor William Hartnell in the first three series from 1963 to 1966 and the tenth anniversary story The Three Doctors from 1972 to 1973. The character would occasionally appear in the series after Hartnell's death, most prominently as portrayed by Richard Hurndall in the 1983 multi-doctor special The Five Doctors, and as portrayed by David Bradley in the 2017 Twelfth Doctor episodes "The Doctor Falls" and "Twice Upon a Time" and in the 2022 Thirteenth Doctor episode "The Power of the Doctor", the latter previously having portrayed Hartnell himself in the 2013 biopic An Adventure in Space and Time.

David John Bradley is an English actor. He is known for his screen roles including Argus Filch in the Harry Potter film series, Walder Frey in the HBO fantasy series Game of Thrones, and Abraham Setrakian in the FX horror series The Strain.