[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.

[21][22] In Round 25 against the Wests Tigers at Canberra Stadium, he started at halfback in the NRL for the first time, as the Raiders went on to win 27-12.

[30] 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.

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.