Mauriello was a founding member of the band Zebrahead,[1] with lead guitarist Greg Bergdorf and drummer Ed Udhus (both formerly of the band 409), and bassist Ben Osmundson (formerly of the band 3-Ply); they began collaboration through sharing the same rehearsal space, forming Zebrahead to incorporate musical elements of ska-punk and hip-hop, while recruiting rapper Ali Tabatabaee.

Mauriello had founded the band Darling Thieves, (then I Hate Kate), while still in Zebrahead, and it became his main focus; Darling Thieves released their first album Embrace the Curse in 2007 (As "I hate Kate", the band was later renamed after Justin's ex-girlfriend threatened a lawsuit), with music videos for the singles from the album: It's Always Better and Bed of Black Roses.

[2] Mauriello's solo EP, titled How's Life In California, was released via streaming on Spotify on January 13, 2015.

In October of 2019, he formed a new project called Z3N Mafia and released the track "InstaFamous" with former Zebrahead member Greg Bergdorf.

In April of 2020, Mauriello reunited with members of Darling Thieves and released two new songs, "Are We Too Old To Feel This Young" and "Electric Avenue", a cover of the Eddy Grant track.