The first cut of the film was considered disastrous by all involved. Editor Ralph Rosenblum worked for more than a year to save it, with director William Friedkin long gone. The extensive use of period film clips was Rosenblum's idea. The technique of returning from these clips to the movie by starting with a black-and-white version of a shot and changing to color was invented accidentally when the editor's assistant couldn't find the color copy of a piece of film fast enough.
Because of the excessive overtime generated by shooting around the death of Bert Lahr, Norman Lear gave gifts of initialed Tiffany silver money clips to many of the crew members, at the wrap party.
Tony Curtis was offered the role of Raymond Paine but declined due to disagreements over the script and was replaced at a month's notice by Jason Robards. The role of Billy Minsky was offered to a young Alan Alda but he was unavailable due to his commitment to "The Apple Tree" on Broadway.