He played for the Dragons, with whom he won the 2010 NRL Grand Final, and the Penrith Panthers in the National Rugby League.

Merrin has also played at representative level for NSW Country, New South Wales Australia, NRL All Stars and the Prime Minister's XIII sides.

[5] He made three appearances in his debut season for St. George Illawarra as the club won the Minor Premiership but lost both matches in the finals series.

He was a prominent squad member of the 2010 premiership-winning St. George Illawarra team, and came from the bench to play in the 2010 NRL Grand Final.

[9][10][11] After departing Penrith, Merrin signed a contract to join English Super League team Leeds.