In 1983, a year before he did Ghostbusters, Bill Murray made a guest appearance in the short-lived teen sitcom Square Pegs.
The series followed two awkward teenage girls, Patty Greene (a 16-year old Sarah Jessica Parker) and Lauren Hutchinson (Amy Linker), as they tried to fit in at Weemawee School. In episode 18 (From February 14th, 1983) Murray appears as a substitute teacher.
The creator, Anne Beatts, - who based the sitcom on her own experiences - was a former writer for Saturday Night Live and presumably called in a favour from SNL alumnus Bill Murray to make an appearance. You get the feeling from watching his performance that she wrote the lines with him in mind, or just let him go off and do his own thing. Here are the Murray bits from the episode in which he sets the kids up with mock marriages to teach them about life.
Of course you wouldn’t be allowed to say and do a lot of those things on a teen sitcom today. (Referring to a black student as “chocolate girl”? Really?) But from the lame hand buzzer gag to the character seemingly wearing a pyjama shirt with tie, it’s a very Murray performance.
Although it was a show about two teenagers it was actually put in the primetime 8pm slot and was well received by critics but failed to attract a big enough audience to avoid being cancelled after just one season. But here, for just one episode, they managed to get Murray as a guest which pretty much justifies the existence of the whole series.