Rosie was a character who appeared in a total of ten episodes of the CBS-TV series M*A*S*H. The role was played by three different actresses, first, by Shizuko Hoshi (who would play various characters in several later episodes) in the Season 3 episode "Mad Dogs and Servicemen", then by Frances Fong in "Bug Out" in Season 5, she also played her in the season 6 episode "Fallen Idol" when she served Radar and Hawkeye their drinks, which they swapped at the end because of Hawkeye's leaving OR because of his being hungover the night before, then by Eileen Saki in the final eight episode appearances through Season 10 of the series.
The switching of actresses in the role of Rosie mimics the actual handing over of the real-life 'Rosie's Bar' during the Korean War from mother to daughter. Alan Alda became aware of this when he received a letter from the real 'Rosie Jr.' about the incident in the early 1980s, a copy of which is available in the book The Last Days of M*A*S*H by Alan Alda and wife Arlene Alda.
Rosie is the owner and proprietor of Rosie's Bar, the local watering hole for any G.I. to relax, have a few drinks, and, namely the people who worked at the 4077th, eat anything other than the swill served at the Mess Tent.
In the Season 8 episode "Captains Outrageous", Rosie was laid up sick in O.R. with cracked ribs after getting caught up in a big bar fight sparked by an argument between a Turkish and a Greek soldier. She was unable to return to the bar, so the surgeons helped her out, taking shifts tending bar while she recovered.
Major Winchester, while tending bar, refused to serve an Australian Army MP named Muldoon unless he paid for his drink. Winchester was unaware of an agreement Muldoon had with Rosie where he allowed the establishment to operate, provided he received free liquor when he ordered coffee, which was really brandy in a coffee mug. As a result, Muldoon declared the place off limits. At the end of the episode, when she wondered why, Muldoon asserted "You shouldn't have left 'Chauncey Uppercrust' (what he sarcastically dubbed Charles) here behind the bar!" Then an angry Rosie retorted back at Charles "I'll get you for this, Chauncey!"
Rosie's final appearance was in Season 10's Snap Judgement. She informed Klinger about a place called "Little Chicago" where items were being sold by the Korean black market. Klinger was attempting to recover Hawkeye's stolen Polaroid camera. When Klinger was being investigated as a suspect for stealing the camera, Rosie almost ruined Klinger's chances of being cleared when she inadvertently mentioned Little Chicago in front of the investigator, thus re-opening the case against him.
- Rosie (M*A*S*H character) at the Internet Movie Database (IMDb)