Jon Lovitz auditioned for the movie when Howard Zieff was the director, and wasn't cast. When Penny Marshall took over from Zieff, she offered Lovitz a role. She was friends with Lorne Michaels, and had seen Lovitz's work on Saturday Night Live.
According to Penny Marshall's memoir 'My Mother Was Nuts,' the script had numerous versions. Nancy Meyers and Charles Shyer wrote one for Shelly Long as the star. A version by David Mamet was filled with profanity.
Adding to the classic rock theme running throughout the movie, Terry's boss' name is James Page, after Jimmy Page.
The Original Cole's Restaurant featured in the movie (the scene where Whoopi is abducted in a phone booth) is not in NYC where the film is set. Cole's is the oldest operating restaurant & bar in Los Angeles and is located at 118 East 6th Street in downtown L.A. It is not only a famous claimant of the first French Dip sandwich (contested by nearby Phillipe's), but being close to LAPD headquarters, it is widely known as a cop bar. It has been featured in several films and television shows.