Chapeltown, Leeds born right half Harold Kay began his football career as a centre forward after the First World War playing for local junior club Thorncliffe United from where he joined Second Division Barnsley in July 1920, making his Football League debut at Sheffield Wednesday that September, before converting to the half back line the same season and making his first appearances at right half in March 1921. Never more than a fringe player at Oakwell, he made 15 appearances for The Tykes over three seasons before joining Southend United in June 1923, spending a single season at The Kursaal, scoring once in 11 appearances.
He joined Barrow in June 1924, where he was a near ever present in their 1924-25 campaign, scoring 5 goals, 4 from the penalty spot, in 47 appearances, but once again moved on after a single season in Cumbria, this time joining Crewe Alexandra in July 1925, where he was a near ever present for his first two seasons, and an ever present in 1927-28, scoring a remarkable 12 goals in the campaign (seeing that only one was scored playing as an emergency striker!).
After 26 goals in 130 appearances for The Alex, he joined Midland League Mansfield Town in the 1928 close season, where he was a prominent member of their 1928-29 Midland League Championship winning team, scoring 16 goals in 82 appearances for The Stags before joining Wombwell in the summer of 1930. Having been re-instated as an amateur he finished his career with Barnsley Ministry of Labour in 1935.