Robert Clarke attended Mosman Preparatory School and then the Shore School in North Sydney.

He was selected in the 1981 Australian Schoolboys Team which toured the United Kingdom, Ireland and the United States of America.

The team was undefeated in 14 games, having only one try scored against it. One of the most successful Australian Schoolboy teams over the last 30 years, it produced 11 future Wallabies including Michael Lynagh, Steve Tunyman, Tim Kava, brothers Brad and Matthew Burke, David Knox, Brett Papworth, Ian Williams and Cameron Lillicrap.