He made four appearances in the senior team in the 2013-14 season, He played for
Emerging Ireland (effectively the third XV of the
Irish rugby team) at the
2014 IRB Nations Cup in June 2014. He signed a development contract ahead of the
2014–15 season, during which he made fifteen appearances, including nine starts, He was part of the Emerging Ireland team that won the
Tbilisi Cup in June 2015. In
2015–16 he made 23 appearances for Ulster, including 21 starts, scoring four tries won his first senior cap for Ireland against
England in the
2016 Six Nations Championship, He made his 100th appearance for Ulster in February 2019. He made his third Ireland cap, scoring a try, against the
USA in the
2018 end-of-year rugby union internationals. and won Player of the Year and Supporters Club Player of the Year at the Ulster Rugby Awards. In
2019–20 he made 17 appearances, all starts, and scored three tries. In
2020–21 he made 15 appearances, all starts, scored two tries, He played for Ireland against
Georgia in the
2020 end-of-year internationals, and against
Japan and the USA in July 2021. He started all three of Ireland three tests in the
2022 end-of-year internationals, and was named in the Irish 6 nations squad for 2023 on the 19 January 2023. He started in Ireland's 34-10 victory over Wales in the opening week. He was called up to the Ireland squad for their two-match
tour of South Africa in July 2024. He made his 200th appearance for Ulster in a home win against the
Stormers in March 2025. McCloskey featured in Ireland's record 106-7 win over Portugal on 12 July 2025, scoring the opening try in the first minute. He was one of only two Ireland players who played every minute of all five matches of the
2026 Six Nations Championship, after which Ireland coach
Andy Farrell said "He should definitely be in the running for player of the tournament." He made the most "dominant contact" collisions (18), and was joint top in try assists (6) and turnovers won (8), and led Ireland in carries (74), offloads (8), defenders beaten (20) and post-contact metres (105). McCloskey tries not to get too psyched up for big matches, preferring to conserve nervous energy for the day. == Honours ==