He is a first-generation American; both his parents emigrated from Ireland.
His father was an automotive engineer, and Brian wanted to follow in
his father's footsteps. However, when his father passed away when Brian
was 15, he no longer wanted to be an automotive engineer, and
discovered acting.
Since _Clerks (1994)_, Brian O'Halloran has primarily been a stage actor, working with the Boomerang Theatre Company, the New Jersey Repertory Company and the Tri-State Actors Theatre, among others.
In all movies he has appeared in that were directed by Kevin Smith, his character's last name has been Hicks.
Brian was active in his high school theater club, and continued on
through college.