Karl Harrison started his career at Bramley where he developed a reputation as a tall, wiry but strong running second-row forward. As he bulked up, he made the customary step up to the front row, but kept his pace and ball handling skills. In November 1985 Karl was signed for £15,000 by George Pieniazek, the then Rovers coach, to help plug a hole in the first team squad. After settling down to the pace of the top flight and having helped Rovers to avoid relegation at the end of his first season, Karl found himself back in the second division when Rovers were relegated in 1987. This proved to be a turning point in Harrison’s career as his game really developed under new coach Peter Fox. Rovers bounced back into the top flight, and Harrison played a prominent role all year, including the Second Division Premiership final against Oldham at Old Trafford. However, the following season was his best year yet. In a young team that largely overachieved, Harrison really started making a name for himself in the front row alongside Jeff Grayshon and Trevor Clark. Rovers finished sixth in the league and almost made it back to Old Trafford for the First Division Premiership final, losing the semi-final at Hull after a stirring win at Leeds.
Unfortunately that was Karl’s last match for Featherstone. He was unsettled over the summer, and despite being relatively cashed up following the sale of Graham Steadman, the club refused to meet Harrison’s increased wages demand and he was transfer-listed. When Hull came in with an offer of £57,500 Rovers accepted it as the club was reluctant to go back to the RFL tribunal to set a fee having done well out of the Steadman deal. He had played 114 games for Featherstone and notched a reasonable 16 tries in that time. He once scored a hatrick for Rovers, versus Barrow in April 1987.
At the Boulevard, Karl linked up with influential Australian coach Brian Smith and, within a year of leaving Featherstone, Karl was leading the Great Britain pack at Wembley against Australia. After two seasons at Hull, he moved to Halifax where he finished his career with a total of 14 Great Britain caps, being a Lions tourist in 1992. He then started coaching and his first head coach appointment was at Keighley, before moving to Bradford as assistant to Brian Noble, before finally getting a chance to be a super league head coach at Salford. From there he went to Batley and then Halifax.