In 1975, the Off-Broadway The National Lampoon Show led to Bill's first television role as a cast member of the ABC variety show Saturday Night Live with Howard Cosell. That same season, another variety show, NBC's Saturday Night, premiered. Cosell's show lasted just one season, canceled in early 1976.
After working in Los Angeles with the "guerrilla video" commune TVTV on several projects, Murray rose to prominence in 1976. He officially joined the cast of NBC's Saturday Night Live for the show's second season, following the departure of Chevy Chase. --WP
I was just a child for Bill's SNL days, but he and John Belushi left a mark on me, I'll concede.
Years later, Murray very modestly attended the David Letterman: Mark Twain Prize ceremony at the Kennedy Center, ~2018. You can see how it went down here:
He looks like he's playing Mike Dawson