[1] After a successful loan period he was granted a release from Bramall Lane and signed for Halifax Town in June 2003 where he remained for five years amounting over 200 appearances and scoring 44 times.

[2] The player remained at Crawley Town for two seasons, turning down new deal in June 2010 to concentrate on completing his degree to become a physiotherapist.

[3] During his stay at The Broadfield Stadium, Killeen appeared in fifty-eight league games, scoring seven times in the process.

In July 2010, it was announced that he had signed for Droylsden in the Conference North where he remained for three years amounting over 150 appearances.

He had a brief spell at Ashton United, however has not played competitively since gaining a 1st class honours degree in physiotherapy.