He was also a founder and lead singer for The Bruisers, which he helped form in 1988 in Portsmouth, New Hampshire.

In February 2022 it was announced that Barr was forced to drop off of the Dropkick Murphys' 2022 St. Patrick's Day Tour and their 2022 summer tour in Europe to take care of his ailing mother, who is battling Lewy Body Dementia.

In 2023, Barr provided guest vocals on The Defiant song "Where Did Lady Liberty Go?"

and on August 31, 2024, Barr made a surprise appearance during The Defiant's set where they were opening for NOFX in Brockton, MA.

Dropkick Murphys opened for NOFX the following day however Barr did not join them for their set.