William Hartnell (in-universe)

You may be looking for the real William Hartnell or Billy from "Pier Pressure", implied to be a young William Hartnell.

William Hartnell portrayed Dr. Who in the television series by 2065. He was too busy to reprise the role in the theatrical film Dr. Who and the Daleks, leading to a new take on the Doctor being played by Peter Cushing in the film instead. (PROSE: Lady Penelope Investigates the stars of the Sensational new film Dr. Who and the Daleks!)