Mills previously played for Gloucester and Worcester Warriors in Premiership Rugby. He made his first appearance for Gloucester in the 2010/11 season coming off the bench in an away match to Saracens where he kicked a conversion in a 35–12 defeat. His most memorable moment for Gloucester came in an away match to rivals Bath the following season where he successfully kicked a late penalty to gain a 14–11 win.[1]
On 28 January 2014 it was announced that Mills would be moving to Worcester Warriors for the 2014–15 season.[2]
In May 2017 he was invited to a training camp with the senior England squad by Eddie Jones.[3]
On 4 March 2020, it was announced that Mills have signed for Premiership rivals Wasps from the 2020–21 season.[4] He was made redundant along with every other Wasps player and coach when the team entered administration on 17 October 2022.[5]
On 11 November 2022, Mills signed for Premiership rivals Sale Sharks for the rest of the 2022–23 season.[6]
