He was still eligible for the minor grade when he won his first Antrim SHC medal after a defeat of Loughgiel Shamrocks in 1983.
McKillen made his senior team debut in 1984 and went on to win seven Ulster SHC titles in a ten-year period between 1989 and his retirement in 1998.
[5] McKillen first became involved in coaching as a result of his day job as a caretaker at Cross & Passion College.
McKillen later became involved in inter-county management as a selector with the Antrim senior hurling team that won the 2006 Christy Ring Cup after a defeat of Carlow in the final.
[6] McKillen later served as a coach with the Down senior hurling team that lost the 2009 Christy Ring Cup final to Carlow.