Season one began broadcasting in the US in September 1972 and each episode featured a laughter track - not employed in the British broadcasts - insisted upon by CBS executives despite protestations by series producers Larry Gelbart and Gene Reynolds. Spearchucker Jones (Timothy Brown) and Ugly John (John Orchard) were introduced as supporting characters, but were dropped by the end of the season. Twenty-four episodes were made and highlights included a boxing match between Hawkeye (Alan Alda) and Trapper John (Wayne Rogers), Hawkeye faking insanity when Henry Blake (McLean Stevenson) is away, and a bomb containing leaflets exploding after the wrong wires were cut.
Concessions were made regarding the laughter track from season two when producers were allowed to omit it from operating scenes. Sidney Freedman (Alan Arbus) and Colonel Flagg (Edward Winter) were introduced in this season. Highlights of the 24 episodes in season two included Hawkeye acting even more erratically than normal after being sleep-deprived for days, the camp coming under fire from a sniper in nearby hills, and a woman showing up with a baby she insists is Radar's (Gary Burghoff).
During the third season, Klinger (Jamie Farr) gets married and Henry Blake is killed in a plane crash on his way home. Other highlights included Major Burns banning alcohol, Hawkeye and Trapper John playing matchmaker while carrying out examinations of soldiers seeking permission to marry locals, and a stray dog biting Radar. Wayne Rogers filmed his last episodes as Trapper John in this season.
The fourth season opened with an hour-long episode, where viewers were told that Trapper John had received his orders to go home and Mike Farrell made his first appearance as BJ Hunnicutt. The season also saw Harry Morgan arrive as Colonel Potter, replacing Henry Blake as the commanding officer. Other highlights included a bombardier believing he was Jesus Christ, Major Burns discovering that his wife wanted a divorce, and Hawkeye reuniting with his ex-girlfriend (Blythe Danner).
Season five aired between September 1976 and March 1977. The highlight of the season was the marriage of Houlihan (Loretta Swit) to Penobscot (Beeson Carroll) in the final episode. Other highlights include Hawkeye being blinded after a heater he was fixing in the middle of winter explodes and Father Mulcahy's quarantine.
Season six of the comedy series aired between September 1977 and March 1978. Cast changes included the departure of Larry Linville as Frank Burns - he left after finishing season five - and the arrival of Winchester (David Ogden Stiers). Radar is wounded while travelling to Seoul on Hawkeye's advice, Hawkeye develops romantic feelings for a woman with an ailing elderly mother, and a visiting Colonel (Charles Aidman) unemotionally calculates how many soldiers will die in an upcoming battle.
Season seven's 26 episodes aired between September 1978 and March 1979. Highlights included an hour-long clip show, an episode told entirely in the first-person through the eyes of a soldier wounded in battle, and BJ Hunnicutt becoming a surrogate father to an impoverished Korean family.
The sitcom returned to US television in September 1979 for another 25 episodes. Gary Burghoff filmed his last episodes as Radar, Klinger (Jamie Farr) stopped wearing women's clothes, and Father Mulcahy (William Christopher) was promoted to Captain. Congressional aide (Lawrence Pressman) accuses Houlihan of being a Communist sympathiser, Hawkeye saves the life of a woman who turns out be a North Korean saboteur, and Colonel Potter (Harry Morgan) leaves for Tokyo under mysterious circumstances.
The sitcom returned to US television in 1980 for a ninth season, shown between September 1980 and March 1981. Klinger discovers his ex-wife is marrying his best friend, Hawkeye bets BJ Hunnicutt that he can go 24 hours without cracking a joke, and Winchester becomes unusually introspective after a brush with death.
MASH returned for a tenth season in 1981. Twenty-two episodes aired in the US between October 1981 and April 1982. Hawkeye writes a letter of complaint to President Truman about the bureaucracy he faced when ordering new supplies, a famous boxer (Pat McNamara) arrives on a publicity tour, and anxious to beat the Marines at something, Colonel Potter arranges a bowling match.
The final run of 16 episodes began broadcasting in the US in October 1981. The season marked the end of the Korean War and included the staff trading ghost stories on Halloween during surgery, Winchester and Hawkeye planting a rumour that Marilyn Monroe was visiting the camp, and a wounded American soldier (Craig Wasson) learning some harsh lessons when he develops a friendship with the North Korean he wounded. The final episode was broadcast in the US on February 28, 1983.