According to the book Cassavetes on Cassavetes, John Cassavetes originally only wanted to sell the screenplay to Columbia pictures, which he finished early in 1979. However, once Barbra Streisand turned downed the offer to play the lead role and it was offered to Gena Rowlands, Columbia offered him the chance to direct.
Post-production on the movie was complete by the end of 1979. Columbia waited a year to release the picture because they did not believe it would fare well at the box office.
Cassavetes employed an unusual and rather ingenious method to cast Juan Adames as the character of Phil: He held a casting call in a New York disco with hundreds of children and their parents together in the same room. A lot of the parents complained, but Cassavetes wanted a child who was tough enough to stand out in such an intimidating situation.
The movie was first conceived as "One Summer Night" and was originally written for MGM as a Ricky Schroeder vehicle. Schroeder, who had recently appeared in the hit movie The Champ, was unavailable, so MGM lost interest and Columbia bought it.
Cassavetes wrote a sequel in the late 80s entitled "Gloria 2". It was briefly mentioned in a Chicago Tribune article published on February 28, 1989, twenty-five days after his death, that Gena Rowlands would appear in the film, but it never got made.