Capt. Benjamin Franklin “Hawkeye” Pierce
An agent of chaos whose brilliance as a surgeon is equal to his irreverence toward military tradition and convention. He arrives at the 4077th in a stolen jeep and leaves in the very same jeep. A man of the people, Hawkeye values human life and honesty about one’s failures in character to military tradition and hypocrisy.
Capt. John Francis Xavier "Trapper John" McIntyre
Graduate of Dartmouth where he played QB on the football team, he shows up at the MASH camp some time after Hawkeye has already turned the place upside down. He becomes Hawkeye’s partner-in-crime and enjoys playing practical jokes and deflating the pomposity of others much like Pierce
Duke Forrest
Duke arrives with Hawkeye in the stolen jeep under the mistaken assumption that his fellow surgeon is nothing more than his driver. He is Hawkeye’s partner in chaos initially, but is replaced by Trapper John once he arrives.
Major Margaret “Hot Lips” Houlihan
The object of Hawkeye and Trapper John’s ire because of her rigid allegiance to a military protocol that seem to them ridiculously out of place in a hospital so close to the front line of battle. She is respected as a nurse, but her personality and hypocritical affair with another surgeon result a practical joke that literally leaves her naked for all to see.
Major Frank Burns
Another object of scorn by the enlisted officers because he is judgmental in his religious beliefs yet has an adulterous affair with Maj. Houlihan which gives her the nickname she hates. He is goaded into physically assaulting Hawkeye which results in his expulsion from the 4077th for good for being under mental duress.
Cpl. Radar O'Reilly
Very efficient manager of the 4077th who seems to possess some form of ESP in that he usually shows up by his commanding officer’s side seconds before he is called and rattles off orders almost in perfect sync with the CO.
Capt. Walter Koskiusko "The Painless Pole" Waldowski
The camp’s dentist for whom Hawkeye arranges a last supper in advance of his planned suicide. The Painless Pole is despondent after a failed sexual encounter and sees no reason to go on living. Hawkeye fakes the suicide pill and arranges for a nurse who will be leaving for home the next day to prove to Waldowski that life is still worth living.
Col. Henry Blake
The relatively ineffectual CO of the 4077th who comes under fire from a Hot Lips about letting Hawkeye and Trapper John run roughshod over military rules of engagement. His dependence on Radar to keep the camp running is clear to everyone, but goes unaddressed.