Union Suit TV Trivia:

Name the series, actors and their character names in this popular TV show...

Added January 25, 2023: M*A*S*H, of course, was one of the most popular tv shows in America; David Ogden Stiers played Major Charles Winchester (shown below in his long underwear) and William Christopher played Father Francis Mulcahy (driver of the jeep).

That was Quick!!  Okay smarty pants... Here are Bonus Trivia Questions added January 20, 2023:

What was the name of the episode? "Out of Gas"

Why did the major end up wearing only his union suit? He had gone with Father Mulcahy to dicker with black marketiers, trading his expensive wine for sodium pentothal, an anesthetic for wounded soldiers in triage. The marketiers took offense at his pompous negotiating technique so stripped him of his new winter coat as well as his hat and clothes, leaving him wearing just his long underwear.

When did the episode air on TV and on which network? Episode 13 of Season 7 aired on the CBS television network December 4, 1978, forty-four years ago, if you can believe that.

Here are some additional photos of that 160th episode, streaming now everywhere:  

An even funnier episode of M*A*S*H was featured here in Union Suit Fan March 6, 2019. It was called the "Longjohn Flap."  That posting is repeated below:

The Longjohn Flap      

In Season 1, Episode 19 of the long running popular TV show, M*A*S*H, a severe cold front hits the U. S. triage camp in Korea. Fortunately for Hawkeye Pierce, his dad had sent him a suit of warm one-piece underwear just in time for the winter weather. The union suit was far superior to the regular army issue long johns typically provided to the troops. Just before bed time, Hawkeye strips down to the "double-weave, semi-woolen, sensuously soft" long underwear. 

Seeing him, Trapper John, coughs pitifully and reminds Hawkeye of the terrible cold he is experiencing. He asks for the warm union suit. Finally, kindhearted Hawkeye is convinced that Trapper needs the underwear more than he to keep from getting pneumonia. He pulls off his new underwear and throws them over to Trapper.

The next night Trapper looses Hawkeye's long underwear to Radar in a poker game. After wearing them for only one night Radar nearly gives the union suit to a good-looking nurse but decides instead to trade them to the camp cook for a leg of lamb and mint jelly dinner. 

Before the cook can wear them, Frank appears in the kitchen to warm up by the stove. There he conducts a surprise inspection and, finding the kitchen unhealthy, threatens the cook. The cook decides he doesn't really want the union suit after all and offers then to Frank who takes them and doesn't pursue his threat. With the acceptance of the long johns the cook is not reprimanded.

Back in the tent Frank shares with Hawkeye and Trapper, he quickly pulls on the underwear. The boys see him buttoning up and are understandably seething mad that their nemesis has ended up with the union suit. Frank sleeps with a baseball bat to protect his recently gotten gain.

The next day Hotlips Hoolihan realizes Frank is wearing civilian long underwear and demands he give them to her. He does, but before she can wear them, they are stolen from her tent!

The thief turns out to be Klinger who had heard that Frank was wearing the warm underwear. He ordered Frank by gun point to strip and give them over. Apparently he was going to don them under his skimpy dress. Frank informs Klinger that he has given the union suit away. Klinger realizes that they are now in Hotlips' tent so steals them with his bayonet. But guilt overcomes the cross-dresser and in a confession decides to give them to Father Mulcahy. 

Father wears them to bed but soon thinks better of it and so the next day gives the union suit to Colonel Henry Blake, Commanding Officer. Surely, Henry will get them to their rightful owner.

Just as Henry is happily buttoning up the prized underwear, Hawkeye and Trapper appear in his office to report the missing union suit. 

They can't believe Henry is wearing Hawkeye's underwear. They want them back. During the discussion, Henry has an attack of appendicitis. The boys insist that Henry get operated on immediately. Henry at first refuses.

They take Henry to surgery, still in the long underwear, and begin to immediately operate. 

Henry and the union suit are saved and Hawkeye gets his underwear back from his grateful commanding officer. Presumably, Hawkeye retains his long underwear for the remainder of his time in Korea.

Thanks to CBS and the long underwearing Cast of M*A*S*H.