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.
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).
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.
During production, Bill Murray and Hunter S. Thompson engaged in a series of dangerous one-upmanship contests. "One day at Thompson's Aspen, Colorado, home, after many drinks and after much arguing over who could out-Houdini whom, Thompson tied Billy to a chair and threw him into the swimming pool. Billy nearly drowned before Thompson pulled him out."
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".
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.
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.
Hunter S. Thompson met with the film's screenwriter John Kaye and felt that Kaye understood more than what was in the script, which he described as "bad, dumb, low-level, low rent". Thompson admitted that he signed away having any kind of control so that he could not be blamed for the end result.
Hunter S. Thompson was eventually brought aboard the film's production as "executive consultant", but claimed he had no substantial role other than to have "wandered around and fired machine guns on the set".
In the original script, Lazlo's surname was Mendoza but this was changed after Nosotros, a group of Chicano actors and filmmakers, threatened to create controversy if the character was played by Anglo actor Peter Boyle.
Ralph Steadman observed Art Linson on the set and said that it was "pretty obvious that he was in no frame of mind to catch the abandoned pure essence of gonzo madness, which can only happen in uncontrolled conditions". He also felt that Linson's "fanaticism for the subject he was trying to portray was undoubtedly there, and his sincerity, too", but felt that he was under the impression that the film was a runaway hit before he had even begun filming it and therefore refused to take any chances with the material.
Because of the high cost of music licensing, most VHS and all DVD releases have retained only the Neil Young score and the Creedence Clearwater Revival song, "Keep on Chooglin'", with the rest of the music replaced by generic approximations of the original songs. Only the theatrical release and early VHS releases contained the songs found on the soundtrack. The choice of songs for the DVD version was somewhat anachronistic, since it featured 1980s-style songs in a 1960s and 1970s setting.
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 studio (Universal).
In the late 1970s, Thom Mount paid 100,000 dollars for the film rights to Hunter S. Thompson's obituary of Chicano activist Oscar Zeta Acosta, "The Banshee Screams for Buffalo Meat". Thompson agreed to have it optioned without seeing a screenplay figuring that the film would never get made, as the vastly more popular Fear and Loathing in Las Vegas had been optioned several times and was never made.
Bill Murray and Hunter S. Thompson were concerned with the film's lack of continuity and in early 1980 added voice-over narration. When the film was sneak-previewed in late March, the last two scenes and narration were absent. Murray was outraged and the studio ended up shooting a new ending. Three days before it was to be released in theatres a press screening was suddenly cancelled because of editing problems.