To get into character, Bill Murray spent time with Hunter S. Thompson by drinking, shooting and generally having a great time at Thompson's Colorado ranch. After filming ended, Murray continued to act "Gonzo" through the beginning of the next season of Saturday Night Live (1975), to the annoyance and consternation of cast and crew members.
In an early scene, the establishing shot outside a seedy bar contains two seedy characters standing outside it, lighting cigarettes. They are musician Neil Young and music producer David Briggs, who contributed to the soundtrack selection and recording.
The character of Carl Lazlo is loosely based on 1960s Chicano lawyer Oscar Zeta Acosta [See: Oscar Acosta]. Acosta was briefly Hunter S. Thompson's attorney during the 1970s and is the basis for the character of Dr. Gonzo in Fear and Loathing in Las Vegas (1998). The title of this movie is an allusion to Acosta's book "Autobiography of a Brown Buffalo" (1972).
The latter two sections of the film are based on Hunter S. Thompson's books and articles "Fear and Loathing on the Campaign Trail '72" (1973) and "Fear And Loathing At The Superbowl: No Rest For The Wretched" (1973) respectively, and both fist published in 1973, about seven years prior to this film being made and released.
In the beginning of the movie (about 15 minutes into it), while Lazlo is dictating to HST in the car, a cop is busting three guys. The wall they are putting their hands on, has graffiti "Fear and Loathing", which is a tag line of Hunter S. Thompson's.
Ralph Steadman, who did illustrations for Hunter S. Thompson's books, drew the title cards for this movie. The closing titles credit Steadman for "Title Splatters", "Gonzo Calligraphy" and "Incidental Artwork".
Debut theatrical feature film directed by writer-producer Art Linson whose only other directorial credit after this movie was about four year's later with The Wild Life (1984) for the same Universal Pictures studio.
Peter Boyle receives first billing and Bill Murray receives second billing during the opening credits but dvd and video covers, movie posters and promotional materials tend to actually reverse the billing and feature Murray with above-the -title top billing with Boyle getting second.