The role of Prof. Louis Levy, subject of Cliff Stern's documentary in this film, is played by non-actor and therapist friend of Woody Allen's , world-renowned Martin Bergmann, clinical professor of psychology in New York University's post-doctoral program.
Lester is based on Larry Gelbart, whom both Woody Allen and Alan Alda worked with and reportedly disliked because of his despotic ways. Lester's various comments such as "Comedy is tragedy plus time" and "If it bends, it's funny; if it breaks, it's not funny" were actual Gelbart quotes. In spite of this reputed dislike for Gelbart, Allen called him "the best comedy writer that I ever knew and one of the best guys" in a statement shortly following Gelbart's death, and Alda said, "Larry's genius for writing changed my life because I got to speak his lines -- lines that were so good they'll be with us for a long, long time; but his other genius -- his immense talent for being good company -- is a light that's gone out and we're all sitting here in the dark." (from the Los Angeles Times obituary)
One-third of the film had Woody Allen's character shooting a documentary on old vaudevillians, with Mia Farrow as the head of the institute to which they belonged. Allen didn't like the scenes in the final cut. During postproduction he cut an entire third of the film, then rewrote and re-shot that section from scratch. As a result, Sean Young's scenes were cut out, and Daryl Hannah's role was reduced to a brief cameo.
Clifford's sarcastic remark to Halley Reed that he loves Lester like a brother; David Greenglass refers to the fact David Greenglass was the brother of executed atomic spy Ethel Rosenberg and that his testimony at their trial help convict her and her husband Julius.
Originally, Alan Alda was only supposed to appear in the opening party scene with Daryl Hannah. Woody Allen expanded Alda's part after he asked Alda to improvise and Allen liked the improvisation. Allen wrote Alda's part as they went along.