 He played at representative level for Great Britain, England and Yorkshire, and at club level for Castleford (two spells) in England, and Manly-Warringah Sea Eagles in Australia, as a , 

He coached at representative level for Great Britain, and at club level for Castleford, Leeds, Halifax, Huddersfield Giants and Hull Kingston Rovers in England, and Newcastle Knights in Australia, taking them to their first premiership in 1997.In 2014 he was inaugurated into the British Rugby League Hall of Fame.Reilly won caps for England while at Castleford in 1970 against Wales and France, and in 1977 against Wales (sub), and won caps for Great Britain while at Castleford in 1970 against Australia (3 matches), and New Zealand (3 matches), and in the 1970 Rugby League World Cup against Australia, France, and Australia.