In January 2012 May was called up to the England Saxons, which he celebrated by scoring two tries from full-back for at Kingsholm against Toulouse in the Heineken Cup. May made his debut off the bench against Scotland, and made his first start against Ireland the following week. In March 2012 May was named as the inaugural winner of the LV= Breakthrough Player Award. May was named Gloucester's Young Player-of-the-Year for 2011/2012, and his stunning solo effort against Harlequins was named Try-of-the-Season at the Aviva Premiership Awards. In December 2012, May signed a two-year contract extension with Gloucester until the end of the 2014–15 season. On 24 October 2014, May signed a new long-term contract with Gloucester Rugby.
May was called up to the senior England tour of South Africa in June 2012, scoring two tries in England's 57–31 win over Sharks. May won his first international cap during England's 2013 summer Tour against Argentina in the second Test which England won 51–26. On 9 January 2014, May was called up for the 2014 Six Nations Championships where he was in the starting fifteen against France, Scotland, Ireland, Wales and Italy. He started the first test against the All Blacks in England's 20–15 defeat, but was dropped for the next two tests.