That was over 37 years ago in 1984.
Today he is 71, and has starred in 88 movies in total, 68 since Ghostbusters was released.
In Ghostbusters, I think Bill Murray looks:
Ghostbusters scores 7.3 out of 10 on The Movie Database.
Bill Murray's first acting role was as 'Nick Kessel (uncredited)' in Next Stop, Greenwich Village, released in 1976 when he was 25.