Dennis Hartley played 202 games for Hunslet between 1961 and 1966. He was an outstanding enforcer in a formidable pack of forwards which created the platform for a very successful period for the club. Hunslet were huge underdogs in the Yorkshire Cup Final in 1962 against Hull KR but triumphed for the first time since 1908 in a game in which Hartley scored a drop goal for the only time in his career. He was one of the outstanding players in the 1965 Wembley defeat by Wigan. He won 4 caps for Great Britain whilst at Hunslet.