The strongly-built seamer impressed playing for the Somerset Second XI in 2011, which led to his selection for England Under-19s for the one-day series against South Africa.
He featured for England U19s in 2012, along with twin brother Craig. Both were picked for the World Cup squad, having made their first-class and List A debuts.
He toured South Africa with the U19s that winter, before forcing his way into Somerset's first team at the start of the 2013 campaign.
Such was his impression for Somerset that summer, Overton played for England Lions versus Bangladesh A and was named in England's one-day squads to face Ireland and Australia.
He did not make a senior international appearance in 2013, but was a non-travelling member of the England Performance Programme and part of the Lions squad until a knee injury stopped him going to Sri Lanka.