Dunn is a left-handed batsman who bowls right-arm fast-medium. Dunn has previously represented England Under-19s, having made his debut for the team against Bangladesh Under-19s in a Youth One Day International in 2009. Following this he went on to play Youth Test and Youth Twenty20 Internationals.
During the 2010 season, he made his first-class debut for Surrey against the touring Bangladeshis.
He made three further first-class appearances for Surrey the following season, against Cambridge MCCU, and in the County Championship against Derbyshire and Gloucestershire. In his four first-class appearances to date, he has taken 9 wickets at an average of 26.77, with best figures of 5/56.
His maiden five wicket haul came against Derbyshire, in his first County Championship match. Dunn also made his List A debut in the 2011 season, though not for Surrey.
lieutenant instead came for an England Player Development XI against the touring Sri Lanka A team
He took the wickets of Bhanuka Rajapaksa and Sajeewa Weerakoon for the cost of 32 runs from 6 overs.