Jackson made his senior debut for Ireland in June 2006 against England. He was a member of the Ireland teams that won the 2009 Men's EuroHockey Nations Trophy and the 2011 Men's Hockey Champions Challenge II. Jackson also helped Ireland win Men's FIH Hockey World League tournaments in 2012 and 2015. Jackson captained Ireland at the 2013 Men's EuroHockey Nations Championship and he scored the equaliser in a 3–3 draw against the Czech Republic. This draw secured Ireland's place in the top level of EuroHockey Nations Championship. He has since captained Ireland over forty times. He was also a member of the Ireland team that won the bronze medal at the 2015 Men's EuroHockey Nations Championship. He also represented Ireland at the 2016 Summer Olympics. In June 2017 Jackson was a member of the Ireland team that won the Hamburg Masters, defeating Germany 4–2 in the final. In July 2019, during a two-match series against Scotland, Jackson became the third Ireland men's international, after Eugene Magee and Ronan Gormley, to make 250 senior appearances.