He finished off his debut year in the NRL having played in 8 matches for the Raiders. On 27 September, Cornish was named at halfback in the 2015 New South Wales Cup Team of the Year. On 21 October, he signed a 1-year contract with the Parramatta Eels starting in 2016. Cornish played for the Parramatta Eels who won the 2016 NRL Auckland Nines. After failing to play a first-grade game for the Eels, late in the year, Cornish signed a contract with the Sydney Roosters for 2017. In February Cornish was selected to play in the 2017 NRL Auckland Nines. The Roosters won the final. On 31 October, it was announced by the Sydney Roosters that Cornish had retired from rugby league and will now move into the insurance industry after taking up a job on the Central Coast.