Bentley original club was Hutt Old Boys Marist RFC in New Zealand, where as a Wellington Academy member he played for Wellington U21s and the Wellington XV. In 2007 he was the WRFU Club's 'Rugby Player of the Year'.
On 19 June 2013, it was announced that Bentley would join Gloucester Rugby in the Aviva Premiership on a one-year contract for the 2013–14 season.[3] On 6 June 2014, Bentley returned to the RFU Championship as he signed a contract to join Jersey for the 2014–15 season.[4] On 28 April 2015 Jonny Bentley confirmed his departure from Jersey[5]