Greg Mathew was born on January 31, 1982 in Wagga Wagga, Australia, along with his identical twin brother David.
Greg spent several years at boarding school in Sydney. He both worked and played junior football for the South Sydney Rabbitohs but quit because of injuries. He then worked as a sales representative for Foster's Group in Sydney prior to Big Brother.
He won the reality show Big Brother Australia in 2005, receiving over $800,000 as the prize.