In 2010 Gilroy was promoted to the Ulster Rugby first team. Gilroy scored 8 tries during the 2010–11 Celtic League. Gilroy burst onto the scene and scored his first two tries of the 2010–11 season in a match against the Cardiff Blues which Ulster won 37–15. Gilroy again scored twice the next game against Benetton Treviso when Ulster rugby won 19–9. He then made his tally to 5 tries when he scored against Leinster rugby but it was not good enough and Leinster won 30–13. He was ruled out for two games with an injury but scored a try against Cardiff Blues to make him known a young talent. He scored once again in the 23–10 win over Aironi. During the 2010–11 season, Gilroy's club, Dungannon RFC, came fifth.