One of the main characters in the movie M*A*S*H (1970) is a dentist nicknamed "Painless Pole" or "Jawbreaker." While this character does not appear in the TV Series, his name is mentioned by Hawkeye as one of the people who bought a ticket for the raffling of Lt. Dish in the pilot.
For the first and only time, Father Mulcahy was played by George Morgan. The next time Father Mulcahy appears, and from there on out, he is portrayed by William Christopher.
Gary Burghoff, who plays Walter "Radar" O'Reilly, has a deformed left hand; three of his fingers are shorter than they would normally be. During the course of the series he took great care to keep this hidden; however, during the opening credits when he catches the football and announces "Here they come" (at around 1 min) there is a very clear shot of both his hands around the football displaying the deformity. Ironically, in real life this deformity would have classified him as "unfit for service" in the Army.
Wayne Rogers was originally considered for the Hawkeye role; finding the character too sardonic for his tastes, he asked if he could instead test as Trapper John, who was more upbeat.
The character of "Hotlips Houlihan" was inspired by the real-life Korean War MASH head nurse "Hotlips Hammerly," also a very attractive blonde, of the same disposition, and also from El Paso, Texas.