 On 12 December 2012, it was announced Hamilton would leave Gloucester at the end of the season to join French club Montpellier on a three-year contract.On 28 May 2014, it was announced that Hamilton would leave Montpellier to return to England to join Saracens.On 2 September 2015, Hamilton announced his retirement from international rugby after Vern Cotter had not selected him for Scotland's World Cup squad

In August 2016, Hamilton co-founded a sports marketing company with Ian Ascough called Those Fellas.