In 17 Sep 1969 LAT and Var news items, Alex in Wonderland was announced as an upcoming collaboration between Mike Frankovich, Paul Mazursky, Larry Tucker, and Columbia Pictures, whose Bob & Carol & Ted & Alice (1969, see entry) premiered the night before at the New York Film Festival. Six months later, the 20 Mar 1970 DV reported that Frankovich and Columbia had left the project over “basic conceptual differences between all concerned.” The split was said to be amicable, and Tucker and Mazursky planned to continue working on the film through their joint venture, Coriander Productions. Within days of Columbia’s departure, the 23 Mar 1970 DV confirmed that Metro-Goldwyn-Mayer, Inc. had stepped in to produce and distribute, with production set to begin on 11 May 1970.
       Writer-director Mazursky and co-writer Tucker used their own experiences as a newly successful filmmaking team in Hollywood as the inspiration for Alex in Wonderland, according to an interview in the 26 Jul 1970 NYT. Mazursky stated that in real life he had been offered opportunities to direct films about Lenny Bruce and Malcolm X, which they incorporated into the script. The two also wrote a slight variation on an interaction Mazursky had with a producer following the debut of Bob & Carol & Ted & Alice, in which he was offered a choice of projects and a Marc Chagall painting hanging on the producer’s office wall. According to an article in the 30 Aug 1970 LAT, Mazursky and Tucker decided to end their partnership after Alex in Wonderland. The two worked together again, however, on the Bob & Carol & Ted & Alice sitcom, which aired for one season on ABC between 26 Sep 1973 and 7 Nov 1973.
       A production chart in the 15 May 1970 DV confirmed principal photography began in Southern California on 11 May 1970. In Hollywood, CA, a battle sequence was shot on a stretch of Hollywood Boulevard outside the Musso & Frank Grill, according to the 29 Nov 1970 LAT, and Mazursky’s own home in south Hollywood served as the residence that appeared in a house-hunting sequence, the 26 Jul 1970 NYT stated. Other filming took place on the MGM studio lot in Culver City, CA. For the sequence in which Italian filmmaker Federico Fellini appeared as himself, Mazursky, Tucker, and Sutherland traveled to Rome, Italy, for a day of shooting there. Supplemental filming with Fellini stand-ins was done in Los Angeles, as noted in the 16 Jul 1970 DV.
       The world premiere took place at the Music Hall Theatre in Beverly Hills, CA, on 17 Dec 1970. That day’s DV stated that the event was expected to raise over $7,000 for the Los Angeles Free Clinic. Regular screenings in Los Angeles began the following day, on 18 Dec 1970, and a New York City opening ensued on 22 Dec 1970. Although critical reception was tepid, Mazursky’s turn as “Hal Stern” was acknowledged as the runner-up for Best Supporting Actor by the New York Film Critics Circle Awards, as stated in the 29 Dec 1970 NYT.
       Hal Marshall was listed as the casting director in a 12 Mar 1970 DV brief, and the 6 May 1970 Var named Tom Miller as the unit publicist. Teri Hope Redack and Cherie Latimer were cast in the film, according to the 1 Jun 1970 LAT and 9 Jun 1970 DV. The picture marked the feature film debuts of four-year-old Glenna Sergent, and twelve-year-old Meg Mazursky, who was the real-life daughter of Paul Mazurksy. Choreographer Paula Kelly was set to appear as herself in a beach dance sequence, the 25 Jun 1970 Los Angeles Sentinel noted.
       The songs "The Little Theatre" and "Juliet's Rainbow" are from the score of Fellini's 1965 film, Juliet of the Spirits; and "Le rêve est là" is the theme music from François Truffaut's 1962 film, Jules and Jim.