Klinger was, according to Larry Gelbart, based on stories that Lenny Bruce would dress in a WAVES uniform in an attempt to get out of the Navy (the stories are actually false, based on a comedy bit he did). However in the original script, Klinger was Gay and wanted to stay in the Army, it was his commanding officers who wanted him discharged, but it was felt that a straight man wearing women's clothes for a discharge was funnier and more interesting.
Directed by Cast Member: Alan Alda (32 episodes), Harry Morgan (8 episodes), Mike Farrell (5 episodes), David Ogden Stiers (2 episodes), Jamie Farr (1 episode).
From the main cast, only two actors served in the Army in Korea: Alan Alda and Jamie Farr.
Alan Alda was an Army Reservist who did only six months on active duty.
Jamie Farr, the actor who played Klinger, the man trying to be declared crazy in order to be thrown out of the Army and sent back home, was the only member of the cast who had actually served in Korea. However, during the Korean War, Farr was stationed in Japan. The dog tags that Klinger wears are actually Jamie Farr's from his time in the Army.
In that vein, Mike Ferral served in the Marines in his youth.
McLean Stevenson (Col. Blake in the TV series) died February 15, 1996. Roger Bowen (Col. Blake in the movie) died the next day.
They both died of the same cause too, so because of the very eerie coincidence, the media decide to "stall" news of Bowen's death till the next week thinking it would somehow be less eerie.
According to legend, during the first commercial break of the series finale the city of New York lost all water pressure because of so many people going to the bathroom.
The Other Darrin: Father Mulcahy was played by George Morgan in the pilot episode before William Christopher took over the role.
Margaret Houlihan's fiancÚ, Lt. Donald Penobscot, was played by a different actor in each of his two appearances on the show.
Three different actresses played Rosie, the proprietress of Rosie's Bar, during the course of the show.
There were also several different actresses playing "Nurse Able" or "Nurse Baker" in various episodes. And two different guys voiced the camp P.A. announcer.
The nurses may be an example of not caring, and were simply placeholder names used instead of creating names for unimportant background characters, much as the location of the battle the casualties are coming from is very often given as just "hill 403' (although the stagnation of the front on the later part of the war might be the cause of that).
A vehicle example: in the finale, a tank is driven into the compound by a wounded tanker. After it starts drawing enemy mortar fire, Hawkeye drives it out of the camp. The tank driven into the camp is an M24 Chaffee light tank◊; the tank Hawkeye drives out is an M4 Sherman medium tank◊. The two look nothing alike.
Recycled Script: In season one, Hawkeye and Trapper gaslight a gung-ho colonel (Leslie Nielsen) - with twice the casulaty rate but half the ground - into thinking he has battle fatigue and needs time to cool off. "White Gold", the second last episode of season three, ends with Hawkeye and Trapper removing Colonel Flagg's appendix to send him stateside for sevel weeks. Season seven's "Preventative Medicine" has Hawkeye perform an unnecessary appendecemy on a colonel to stop him from provoking the enemy to attack him so he could take a hill he was ordered to avoid.
Ken Levine, writer of that episode, said it was unintentional, and when they discovered it they were so embarassed they deliberately had it scheduled opposite that year's Academy Awards so fewer people would see it.
A letter printed in TV Guide in the late '70s from a doctor who had really worked in a MASH in Korea said that the craziest antics on the show, including practical jokes and dressing up, were real. They were not far-fetched or unrealistic, just coping mechanisms for the horrific situation these people lived in. Much of what you saw either really happened, or could really happen. Other MASH veterans have pointed out that some of it would not, especially Klinger; he wouldn't have been allowed to go on crossdressing as long as he did.