Who was the first ever actor to play "The Doctor" on "Doctor Who"?

William Hartnell was the first-ever actor to play the Doctor on the popular television series Doctor Who. He portrayed the character from 1963 to 1966. As the original Doctor, Hartnell's portrayal laid the foundation for the iconic Time Lord character, establishing the Doctor's eccentricity, intelligence, and adventurous spirit. His portrayal of the first incarnation of the Doctor endeared the character to audiences and set the stage for the show's long-running success, making William Hartnell an integral part of Doctor Who's legacy.