At a young age Fallon became a personality and broadcaster in Ireland, later moving on to music journalism and photography.
In the late 1960s Fallon moved to London to pursue his journalism career. In March 1969 he scored a coup - an interview with John Lennon at the 'bed-in' in Amsterdam - which was published in the Melody Maker. This led to a further Lennon interview and a job at Apple Records working with publicist Derek Taylor. In 1970 he appeared on Top of the Pops miming the tambourine in John Lennon's performance of "Instant Karma!".  In an alternate clip, Fallon was shown miming the bass guitar. 
Fallon then became publicist for Thin Lizzy and T. Rex - for whom he coined the term "T.Rextasy". He worked and toured with Led Zeppelin during the band's heyday in the 1970s. During the punk rock years he represented Ian Dury.
In the early 1990s, Fallon toured with and DJ'd for U2 on their Zoo TV Tour and wrote a book/journal about his experiences called U2 Faraway So Close. He then started up a multinational club "Death Disco" with Alan McGee, which was variously located in Dublin, London, New York, and sundry other locations. Later in the 2000s he has DJ'd on the road with the groups My Bloody Valentine and The Kills.
In December 2009 he released a solo record "Fame#9" - a collaboration with Jack White on his label Third Man Records. The 7" single is notable for being "3-sided" - the b-side has separate tracks recorded on the left and right stereo channels.
Fallon then went on to perform on stage with varying lineups before forming BP Fallon & The Bandits with Aaron Lee Tasjan (guitar), plus Nigel Harrison (bass) and Clem Burke (drums) both from Blondie. In 2013 the band released their debut album Still Legal on their own Vibrosonic Records. The album included additional playing by Ian McLagan of the Small Faces. In March 2014 he appeared at SXSW with the group Ghost Wolves, as well as The Strypes performing the song Vicious at a Lou Reed memorial concert. Recently released his latest album 'Hot Tongue' as featured on 'The Late Late Show' in Ireland on September 16th 2016 with Emma Lou and the Agenda
- Jones, Allan. "'Blame it on Jack White...' Introducing BP Fallon & The Bandits". Uncut. Retrieved 8 November 2013.
- Blaney, John (2005). John Lennon: Listen to This Book (illustrated ed.). [S.l.]: Paper Jukebox. p. 16. ISBN 978-0-9544528-1-0.
- Fallon, BP. "About BP". Archived from the original on 13 July 2009. Retrieved 2009-07-09.
- Searcey, Dionne (2006-01-09). "Behind the Music: Sleuths Seek Messages In Lyrical Backspin". The Wall Street Journal. Retrieved 2007-02-28.
- "Books by BP Fallon". www.bpfallon.com. Retrieved 2010-01-03.
- "BP FALLON - Fame #9". Instructional. Third Man Records. Archived from the original on 7 December 2009. Retrieved 2009-12-03.
- Steagall, Tim (8 November 2013). "BP Fallon & the Bandits - Still Legal". Austin Chronicle. Retrieved 8 November 2013.