Kiss my hot lips!", Trapper decides the rest of the camp needs to hear them, and so they broadcast Frank and Margaret's tryst over the PA, but their rendezvous quickly comes to an end when they hear themselves over the loudspeaker. When they hear Margaret growling "Ohh, Frank my lips are hot. In the film, Margaret unwittingly gives herself the infamous nickname of "Hot Lips" when she and Frank have a wild tryst in her tent, unaware that the public address microphone has been planted under her cot so that Trapper, Duke Forrest and some others can listen in on them in the orderly room. After they finish the letter, they find themselves mutually attracted to one another.
At this point, she conspires with Frank to write a letter of complaint to army brass. Margaret is even more appalled by all the goings-on in camp, particularly when the others sing a bawdy version of "Hail to the Chief" for Trapper who was just named chief surgeon, and Margaret becomes Trapper's prime target for sexual insults and innuendo. Margaret later gets into a discussion with Hawkeye (Donald Sutherland) to get his opinion about the nurses that work with him, but when she asserts that he shouldn't be so informal with his staff, especially the enlisted, Hawkeye becomes annoyed and, calling her a "regular army clown", gets up and leaves. Margaret is appalled and Blake promises that Trapper will be punished. After he shows her around the OR during surgery, they happen upon Trapper John (Elliott Gould) just as he punches Frank Burns (Robert Duvall) for wrongly accusing an orderly of killing his patient. Margaret's initial arrival at the 4077th is depicted in the 1970 film Colonel Blake (Roger Bowen) repeatedly and incorrectly refers to her as Major O'Houlihan. Sally Kellerman as Houlihan in the 1970 film version of MASH It is unknown whether she served overseas or stateside during WWII. She entered nursing school in 1938 and graduated in 1942, at which point she joined the Army. Margaret once mentioned that she sends half of her salary to her mother as a remittance, half of which goes to get her sober while the other half goes toward bail money. Little is known or revealed about her mother except that she and her father are divorced, that her mother is an alcoholic and a kleptomaniac. In earlier episodes Margaret said that her father is deceased, but he appears in the season 9 episode Father's Day. She cites her father, Colonel Alvin "Howitzer Al" Houlihan, as her role model. She is devoted to her army career, having been born and raised an "army brat". Margaret is a member of the Army Nurse Corps and, as the highest ranking female in the 4077th, she is the unit's chief nurse, a role that she takes very seriously.