From 2011 to 2013, Cornish played for the Raiders' NYC team[3][4] On 7 June 2012, he extended his contract with the Raiders from the end of 2013 to the end of 2015.[5] On 21 August 2012, he was named at halfback in the 2012 NYC Team of the Year.[6] On 13 October 2012, he played for the Junior Kangaroos against the Junior Kiwis,[7] due to a late injury to Lachlan Maranta which resulted in Ben Hampton taking Maranta's spot at fullback and Cornish taking Hampton's bench spot.[8] In November and December 2012, he attended the Blues Origin Pathways camp designed for possible future New South WalesState of Origin representatives.[9] On 20 April 2013, he played for the New South Wales under-20s team against the Queensland under-20s team,[10] playing at halfback and was awarded the Darren Lockyer Medal as Man of the Match in the Blues' 36-12 win at Penrith Stadium.[11] On 27 August 2013, he was named on the interchange bench in the 2013 NYC Team of the Year, making the team for the second year in a row.[12] On 13 October 2013, he again played for the Junior Kangaroos against the Junior Kiwis,[13] this time co-captaining the side alongside Michael Lichaa.[14]
On 27 September, Cornish was named at halfback in the 2015 New South Wales Cup Team of the Year.[27] On 21 October, he signed a 1-year contract with the Parramatta Eels starting in 2016.[28][29]
On 31 October, it was announced by the Sydney Roosters that Cornish had retired from rugby league.
Post playing
After retiring from the NRL Cornish had moved into the insurance industry after taking up a job on the Central Coast.[32] In January 2024, it was announced that Cornish was appointed the Head Coach of the first grade squad for the Goulburn Bulldogs for the 2024 season.[33]