Beginning his career at the age of 16 playing as a winger for Oldham, Liddiard later played primarily as a fullback, five-eighth, or centre for the Parramatta Eels, the Penrith Panthers, the North Sydney Bears, another stint with Oldham, the South Queensland Crushers, and the Hull Sharks.
Born in Penrith, New South Wales, Liddiard is a Biripi (Aboriginal Australian) man through his maternal ancestry.
[4] Liddiard moved to England for the 1985–86 Northern Hemisphere winter when his older brother David was signed by Oldham.
After impressing in a reserve grade game,[3] Liddiard was selected to make his debut in Oldham's first team at the age of 16 years and 17 days.
[3] Liddiard finished his NSWRL/ARL career with one season stints at North Sydney and South Queensland, between which he played for Oldham in England.