An Australia national and New South Wales state representative hooker, he played in the NSWRFL Premiership for the Canterbury-Bankstown Bulldogs, with whom he won the 1980 Grand Final.

He attended Sydney's Canterbury Boys' High School where he played rugby union and was a Canterbury rugby league junior with the St George Dragons JRLFC at Clemton Park before being graded in 1973 to the under-23's side in which year he played in the Preliminary Final against the Balmain Tigers.

The Canterbury club maintained a scholarship scheme for its juniors at the time which supported him financially while he conducted his medical studies.

As a hooker he was a consistent winner of possession in those days of contested scrums and was known for his trademark ability to burrow over for tries from the dummy half position.

Australia's fitness and skill dominance over Great Britain began to show in this series which was a three-nil drubbing to the locals.

In 2007, Peponis was still the chairman and was in charge when personally difficult decisions were made which saw his former 1980 Grand Final teammates Garry Hughes and Steve Mortimer forced out of their positions with the club.