Frazer Hines
Hines' "Doctor Who" debut came in 1966, when he was cast to play the part of Jamie McCrimmon, the companion of the Second Doctor (played by Patrick Troughton). Originally intended as a one-off guest character, Jamie joined the regular cast and appeared in the series from 1966 to 1969. Hines reprised the role in a cameo in the 20th anniversary serial "The Five Doctors" (1983) and as a guest star in "The Two Doctors" (1985). Hines would appear in 117 episodes of "Doctor Who" in all—more than any other "companion" actor in the history of the series. The only actors appearing in more episodes are those who played the first four Doctors. Many of the episodes featuring Jamie no longer exist in the BBC's collection.
Doctor Who (season 1)
William Hartnell portrayed the first incarnation of the Doctor (referred to as "Dr. Who") in this season. The role was originally offered to Hugh David, Leslie French, Cyril Cusack, Alan Webb and Geoffrey Bayldon; David, Cusack and Webb turned down the role as they were reluctant to work on a series, while Bayldon wished to avoid another "old man" role. Lambert and director Waris Hussein invited William Hartnell to play the role; Hartnell accepted the role after several discussions, viewing it as an opportunity to take his career in a new direction. Hartnell had always wished to play an older character in his work, but failed to do so, becoming typecast as a "tough" actor due to his roles in "Carry On Sergeant" (1958) and "The Army Game" (1957–61). Although portrayed as grumpy and antagonistic in early episodes, the Doctor warms to his companions as the show progresses.