He is, of course, best known as Corporal Walter O'Reilly on the TV show MASH. He won an Emmy Award for Best Supporting Actor on a Comedy Series in 1977 for his role.
Before Burghoff hit it big on MASH, however, he was a professional drummer. He also originated the lead character on the off-Broadway version of "You're A Good Man, Charlie Brown" in 1967. He was then cast in the movie version of MASH (1970) directed by Robert Altman. This led, of course, to being cast on the TV series. He appeared as a regular for seven seasons (1972-79).
Here's a clip from MATCH GAME that I found. Gary was on this show a lot during the 70s, often subbing for regular Charles Nelson Reilly while Reilly was on Broadway. They obviously enjoyed having him around. This clip is interesting because the host, Gene Rayburn, congratulates Gary on his then-recent Emmy Award win!
Happy Birthday, Gary Burghoff!
Thank you for all your great performances!