Before entering parliament he had a career as a secondary education teacher and an employee of the children's cancer charity Canteen, and worked in local government administration.

[3] He taught in the PDHPE faculty at Mount View High School for nine years, before seeking a change in vocation where he became a manager at the young people's cancer charity, Canteen.

[citation needed] In the lead-up to the 2011 state election, Barr received a threat in the mail aimed at his pregnant wife and children.

[4] Despite this attempt to have him withdraw his candidacy, Barr was elected as the state member for Cessnock in 2011, despite an 8.1-point swing to the New South Wales Nationals candidate.

[6] He held these positions until June 2021, when he was demoted to the backbench by the newly appointed Leader of the Opposition Chris Minns as a result of factional disagreements.