A product of Methodist College Belfast, Gilroy has developed into one of the game’s most prolific finishers; his electric pace and footwork puts him among the top ranked in the game. He marked his debut season with Ulster in 2010/11 with eight Celtic League tries, and his ascent through Ireland U20s and Emerging Ireland brought him his first full international cap – and a hat-trick of tries – against Fiji in 2012. Gilroy repeated his hat trick of tries for Ireland in the 2017 Six Nations against Italy. Gilroy is one of Ulster's leading try scorers in history.