Playing in the Northern Cricket Union with CIYMS, McCullough has represented provincial teams at various age groups throughout his career.
[2] He began training with the Emerging Knights in 2021[3] and played two games in the Future Series for them, the level just below senior domestic cricket.
[4] The left-arm spinner was back in the Emerging Knights team for the 2023 Future Series[5] but it would not be long before his services were required elsewhere.
On 13 July 2023 McCullough was named in the Munster Reds squad for their upcoming T20 fixtures in Bready having been loaned out by the NCU.
[13] He made his Youth ODI debut against England U-19s during a famous win for Ireland on 21 August 2023, taking 2 wickets and hammering 23*(10).