On 21 December 2015, Turnbull scored 3-04 for St. Francis College when they defeated Scoil Mhuire gan Smál from Blarney to win the Dr. O'Callaghan Cup.
[1] Turnbull joined the Douglas club at a young age and played in all grades at juvenile and underage levels.
On 21 September 2015, he scored three points from right corner-forward when Douglas defeated Sarsfields by 3-12 to 0-13 to win the Premier 1 MHC title.
On 10 September 2017, Turnbull ruptured his anterior cruciate ligament (ACL) during a training session with the Douglas under-21 football team.
[12] On 23 July 2019, Turnbull scored two points from play when Cork suffered a 3-15 to 2-17 defeat by Tipperary in the Munster final.
Turnbull top scored for Cork with 0-08, including seven frees, but ended the game on the losing side after a 5-17 to 1-18 defeat.
[16] Turnbull subsequently made his National League debut on 16 February 2020 when he was introduced as a 60th-minute substitute for Jack O'Connor in a 3-12 to 1-14 defeat of Westmeath.
[17] He was later included on Cork's Munster Championship panel and made his debut as a 72nd-minute substitute for Séamus Harnedy in a 1-28 to 1-24 defeat by Waterford.