Backworth, Northumberland born full back Bill Sampy played junior football for Chopwell Institute in 1923 before following his older brother Tommy in joining First Division Sheffield United in 1924, making his Football League debut at Bury in October 1924, before carving out a regular place in the first team in October 1925, having a run of 27 matches before the end of the 1925-26 season. However he lost his place in October 1926 and was transferred to Second Division Swansea Town in April 1927 after 36 appearances for The Blades. His Swansea career followed a similar pattern. A fringe player in his first full season, he broke into the team in September 1928 and made 27 appearances during 1928-29 before returning to the fringes and leaving the club in 1930 to join Irish League Waterford in 1930 after 42 appearances for The Swans. He returned to England after a single season in Ireland, joining non league Nelson in 1931, where he finished his career.
Sampy was the younger brother of Tommy Sampy who played 14 seasons for Sheffield United as well as once for Barnsley.