Barrett grew up in Bondi, Australia, the son of George and Marguerite Barrett. He left school at 14 to do a few odd jobs before taking on a trade as a butcher around the eastern suburbs of Sydney. He gave up his trade when a hind of beef fell on him and injured his shoulder. While he was on worker's compensation, he completed three writing courses at the WEA (Worker's Education Authority). When his sickness benefits ran out he worked at various jobs: DJ, barman, or went on the dole. His first writing job was gag writing for disc jockeys on Radio 2SM. He also signed up with a casting agent and started acting in commercials and television series and appeared in what he calls classic A-grade clunkers, the movies Bullamakanka and The Empty Beach.
He has gone on to become a successful homegrown true blue Aussie writer. Fair dinkum.