In Los Angeles, Parker met a 12-year-old Jodie Foster, who at the time was about to start the filming of Martin Scorsese's Taxi Driver. About casting Foster as Tallulah and working with her, Parker said:
Music
Parker chose Paul Williams to score the film in order to get a more "palatable" modern sound, and simply because he liked him. Williams had scored Brian De Palma's commercial failure Phantom of the Paradise, but had also written huge pop-radio hits (such as "We've Only Just Begun" (lyrics), and "(Just An) Old Fashioned Love Song"). In fact, Williams would soon win an Oscar for his song "Evergreen" from the film A Star Is Born (1976).
Williams felt that "... the challenge for me was to provide songs that reflected the period ... and yet maintained an energy that would hold the young audience's attention." According to Parker, Williams was writing while on tour, recording songs in different cities, and sending the completed tapes to Hollywood. Arriving during the first pre-shoot rehearsals, the songs had to be accepted and used as they were, with voices by Williams, Archie Hahn, and others.
Neither the director nor the songwriter were comfortable with the results. Williams later wrote "I'm really proud of the work and the only thing I've ever doubted is the choice of using adult voices. Perhaps, I should have given the kids a chance to sing the songs." Parker also commented: "Watching the film after all these years, this is one aspect that I find the most bizarre. Adult voices coming out of these kids' mouths? I had told Paul that I didn't want squeaky kids' voices and he interpreted this in his own way. Anyway, as the tapes arrived, scarcely weeks away from filming, we had no choice but to go along with it!"
The film soundtrack album was originally released as an LP in 1976. In March 1996, Polydor UK released the soundtrack on CD.
Performers include Paul Williams, Archie Hahn, Julie McWhirter, and Liberty Williams.
; Track listing
- "Bugsy Malone" – Paul Williams
- "Fat Sam's Grand Slam" – Paul Williams
- "Tomorrow"
- "Bad Guys"
- "I'm Feeling Fine"
- "My Name Is Tallulah" – Louise "Liberty" Williams
- "So You Wanna Be a Boxer?"
- "Ordinary Fool"
- "Down and Out"
- "You Give a Little Love" – Paul Williams
Filming
The film was rehearsed and shot in the United Kingdom, largely on Pinewood Studios' "H" stage, with locations in Black Park Country Park (Wexham, Buckinghamshire) and primarily the former Huntley & Palmers buildings in Reading, Berkshire.
The "splurge firearm" proved to be problematic. After initial experiments with cream-filled wax balls proved painful, Parker decided to abandon the idea of filming the firearms directly. Instead, the firearms fired ping-pong balls, and a fast cut to a victim being pelted with "splurge" was used to convey the impression of the rapid-firing firearms.
Baio later said making the film was "awesome":