Duncombe joined Canterbury in 1938 and made two appearances that season.
The second being the 1938 NSWRL grand final where Canterbury secured their first premiership defeating Eastern Suburbs in the final with Duncombe scoring his first and only try for the club in the match.
In 1939, Duncombe captained the premiership winning reserve grade team at Canterbury, playing in all games that season.
In 1940, Duncombe became coach of the Canterbury reserve grade team playing some matches as captain-coach.
This Australian rugby league football biography is a stub.