A week into the shoot, Peter Sellers invited Paul Mazursky to his home for a meeting. Given their previous differences, this was a shock in and of itself. At the meeting, Sellers apologized for the misunderstanding and begged Mazursky to take over the direction. Mazursky refused to do it.

This was not a happy period in Sellers's life. He was miserable working in the U.S. and furious that his second wife, Britt Ekland, had signed to make The Night They Raided Minsky's (1968), which was filming on the East Coast while he was working in Hollywood. As a result, he acted out on the set a great deal. At one point, he was convinced the crew hated him and was leaking unfavorable stories about him to the press, so he tried to have them all fired.

During the shoot, Sellers developed a crush on leading lady Leigh Taylor-Young, who was married at the time to her Peyton Place co-star, Ryan O'Neal. That made a huge problem with the scene in which his character is supposed to turn on his hippie sweetheart. Director Hy Averback tried to get Sellers to change the way he was playing the scene to no avail. When Mazursky stepped in and told Sellers his behavior was hurting the film, the actor turned on him, ending the relationship they had just begun to repair.

The beach scenes were shot at Leo Carrillo State Beach in Malibu and Venice Beach.

Concerned that the film was "too Jewish," executives at Warner Bros./Seven Arts insisted that the cantors at Harold's wedding be dubbed, with English replacing the traditional Yiddish in the wedding service.

Originally, the film included interviews with Beat poet Alan Ginsberg and counter-culture guru Timothy Leary, but the studio cut them, claiming most filmgoers had no idea who they were. Sellers would later claim he, Mazursky and Tucker bribed a guard to let them into the editing room, where they recut the film to represent their vision, but Warner's refused to release that version.

To capture the spirit of the counter-culture on screen, composer Elmer Bernstein featured the sitar, an Indian instrument popular among young people, in his orchestrations.

The popular rock group Harpers Bizarre performs the title song, with music by Bernstein and lyrics by Larry Tucker and Paul Mazursky.

The film premiered in New York on October 7, 1968, before opening around the country on October 18.

Warner Brothers/Seven Arts sold the film with the tagline "The saga of Harold...from dedicated lawyer to dedicated dropout." Afraid of the film's humorous depiction of recreational drug use, the studio backed off from Mazursky's suggestion that they make the poster more psychedelic.

Although I Love You, Alice B. Toklas! was still in release when the Motion Picture Association of America replaced the old Production Code with the current ratings system, the film's producers did not submit it for a rating. They simply kept to their original "For Mature Audiences" label on advertising and at theaters.

By Frank Miller