Duggan scored the first ever try for the club and is the club's record try scorer, with 101 over four seasons between 2006 and 2009, including a record 40 in the 2007 season . He was top scorer in the UK in both 2006 and 2007, and was awarded the 'League Weekly' newspaper's Try of the Season award in 2007. His usual position is full-back. He now qualifies to play for Wales.
In August 2009, Duggan, along with five team mates, was ordered to leave the United Kingdom after the UK Border Agency identified breaches to their visa conditions. Celtic Crusaders cancelled Duggan's contract with immediate effect.