Kenworthy served his apprenticeship with Sheffield United and made his league debut for the Blades at Norwich City in April 1976. During his early days, he won England youth honours.[4] He played for Sheffield United for ten years, captaining the club[5] and making 357 appearances in all competitions with 39 goals,[6] which is the most by a defender in Sheffield United's history.[citation needed] In 1986, he signed for Mansfield Town, where he made 100 league appearances and scored the winning penalty to defeat Bristol City in the Football League Trophy final at Wembley in 1987.[7]