The nephew of The West Australian newspaper sports journalist Mark Duffield, he was a member of South Fremantle's 2005 premiership team.
Duffield made his AFL pre-season debut against Collingwood in the quarter-final and also played in the semi-final loss to Geelong.
On 19 April 2006, it was announced that Duffield had been elevated to the senior list as a replacement for Daniel Haines, who had injured his achilles tendon the previous weekend playing for Peel Thunder.
Duffield then made his debut a week later against St Kilda in the controversial game at Aurora Stadium in Launceston, Tasmania.
[4] Duffield is an old boy of Aquinas College, Perth and was School Captain in his final year, 2002.