Twomey joined the Courcey Rovers club at a young age and played in all grades at juvenile and underage levels.
On 10 October 2015, he lined out at left wing-forward when Courcey Rovers suffered a 1-14 to 2-10 defeat by Ahan Gaels in the Minor A Championship final.
[citation needed] On 22 April 2018, Twomey made his first appearance for the club's top adult team in the Premier Intermediate Championship.
[8] He was selected at right wing-forward when Cork faced Tipperary for a second time in the All-Ireland final on 24 August 2019, however, he ended the game on the losing side after a 5-17 to 1-18 defeat.
[10] Twomey made his first National League appearance on 26 January 2020 when he was introduced as a 60th-minute substitute for Conor Lehane in a 1-24 to 3-17 first round defeat by Waterford.