He is best known as the lead vocalist, rhythm guitarist, and main lyricist of the rock band the Gaslight Anthem, with whom he has recorded six studio albums.

He was also a member of the duo the Horrible Crowes, alongside the Gaslight Anthem's guitar technician and touring guitarist Ian Perkins.

Fallon spent his teen years in Hackettstown, New Jersey, where he became close friends with Tom "Tommy Gunn" DuHamel of the band Communication Redlight.

In early 2006, Volpe decided to leave the band and Alex Rosamilia was brought on board, thus bringing together the future line-up of the Gaslight Anthem.

Another song by the original band called "She Coulda Raised the Titanic" later became "1930" on the Gaslight Anthem's album, Sink or Swim.

With the band he has recorded six studio albums, Sink or Swim, The '59 Sound, American Slang, Handwritten, Get Hurt and History Books.

In 2009, he joined Bruce Springsteen on stage for the headlining set at the Hard Rock Calling Festival, performing the song "No Surrender".

On July 29, 2015, the band announced an indefinite hiatus after their European summer tour, which ended with an appearance at Reading Festival on August 30.

[11] On January 20, 2011, Fallon announced on his blog that he had formed the group the Horrible Crowes with his guitar tech, Ian Perkins.

Molly and the Zombies is an Americana/folk group that was formed in 2013 by Fallon with guitarist and Plow United frontman Brian McGee, former Ryan Adams and the Cardinals bassist Catherine Popper, and Scissor Sisters drummer Randy Schrager.

[15] The band performed their first show in December 2013 in Asbury Park, New Jersey, opening for the Bouncing Souls at the Stone Pony.

He also said all of the band's music, which he wrote and didn't feel like using for the Gaslight Anthem, was inspired by Bob Dylan's Highway 61 Revisited album.

[16] Molly and the Zombies performed at The Bell House in Brooklyn, New York, on June 5, 2014, with Jared Hart of the Scandals and Dave Hause as opening acts.

[19] Brian Fallon is a Christian, but he avoids using references to his faith in The Gaslight Anthems music, although religious themes are heavily present in his solo work.

As he stated in an interview with spinner.com referring to the Gaslight Anthem's 2010 album American Slang, "There are no religious songs and there never would be because the four of us, we all have different views, completely different religions...I'm very cautious not to push that on the band.