Mr. Jenkins, a theater manager in Albany, Georgia was convicted of obscenity-related charges in 1972 for showing the film in his establishment, due to its frank depictions of sex and nudity, with police seizing the print of the film and the Georgia Supreme Court upholding the conviction. The U.S. Supreme Court later struck down the conviction in the 1974 Jenkins v. Georgia case, ruling that the movie was not obscene, and the law that was used to convict the manager was unconstitutional. As a result, Avco Embassy re-released the film to theaters using the tagline "The United States Supreme Court has ruled that 'Carnal Knowledge' is not obscene. See it now!".
Screenwriter Jules Feiffer said he had no idea how Jack Nicholson would tackle the multiple levels of the Jonathan and Bobbie fight, in which the character is "defensive, enraged, contemptuous, and bullying". If the actor got half of everything Feiffer had put into the scene on paper, Feiffer said he would be more than satisfied. Nicholson got everything, and on the first take, according to Feiffer. Astonished, Feiffer asked director Mike Nichols what he had told the actor. "Nothing," Feiffer reports Nichols replying with a grin. "I told him absolutely nothing. He came up with it all himself."
According to Jack Nicholson in an April 1972 Playboy Magazine interview, director Mike Nichols asked Nicholson and other cast members not to smoke marijuana while filming on-location in Vancouver, British Columbia, where it was easily available. Nichols thought it dulled performance.
Mike Nichols spent six months looking for the right girl to play Bobbie. He considered and rejected Jane Fonda, Raquel Welch, Joan Collins, Natalie Wood, and Dyan Cannon.
Writer Jules Feiffer originally pitched the concept to director Mike Nichols as a theatre project. After listening to Feiffer's ideas, Nichols said, "I see it as a movie."