Newly a big star, Sylvester Stallone was frequently hounded, screamed at, and sought out to be touched by fans during principal photography on this picture. Thousands of fans from more than one hundred miles away gathered daily to filming locations in Dubuque, Iowa chanting "Rocky! Rocky! Rocky!" from behind rope and police barriers, and frequently only a block away from the on-set filming. Reportedly, Stallone would make about three pilgrimages a day to the security barriers to shake hands with fans, pose for photos taken with their Instamatic cameras, let some of the more daring kiss him. When time did not allow for signing autographs, Stallone apparently would say: "You'd only lose it. A handshake lasts forever!"
Norman Jewison ran into Sylvester Stallone a day after Jewison attended a private pre-released screening of Rocky (1976). Jewison said: "After predicting that Rocky (1976) would be a big success, something that many were questioning at the time, I asked him (Stallone) if he'd like to read the script of my next picture [F.I.S.T. (1978)]. He took it home and called me the next day to say that he wanted to do it. All we had was a verbal agreement. But he kept it. I have to respect him for that. I understand that he was later offered more than a million dollars to do another film instead".
The Cleveland scenes were filmed in Dubuque. Among the reasons given for the selection of Dubuque was the absence of television antennas that would conflict with the look of the 1930s, the era in which the movie's action was to take place.
The scene where the company sign was pulled down in front of the factory could only be filmed once. They only had one sign, which could not be replaced if it was damaged.
The picture is loosely based on the Teamsters Union and the life of union boss Jimmy Hoffa who fourteen years later would himself be the subject of the movie biopic Hoffa (1992), where the title character would be portrayed by Jack Nicholson.