Between 1984 and 1989 McCoy made 16 full senior appearances for Ireland.[1] He had previously represented Ireland at Under-23 [3] and B levels.[4] He made his senior debut on 4 February 1984 against Wales in an 18–9 defeat.[1] He was a member of the Ireland team that won 1985 Five Nations Championship and the Triple Crown.[8] He also represented Ireland at the 1987 Rugby World Cup.[10] McCoy made his final appearance for Ireland on 18 November 1989 against New Zealand.[1]
McCoy joined the Royal Ulster Constabulary on leaving school and was a serving officer during the Troubles. He initially served in Dungannon as a community officer. However he was subsequently transferred to Bangor. In a 2012 Irish Examiner interview with his former Ireland teammate, Donal Lenihan, McCoy says he was moved after the RUC received a warning of a threat to his life. McCoy denied receiving a bullet in the post from the IRA. When travelling to Dublin to play for Ireland, McCoy was escorted by Garda Síochána Special Branch officers.[2][8]