After joining Stoke City as an eighteen-year-old half-back in August 1926, Harold Watson showed early promise and was a regular member of the reserve team that carried off the Central League title in 1927-28. His senior debut came at centre-half in a 5-1 defeat at Leeds United on Christmas Eve 1927, but he had only four Second Division games under his belt in five seasons when Albion signed him in July 1931.
Harold fared little better at the Goldstone where, although he was capable of filling any of the half-back berths, he was forced to play second fiddle to the likes of Reg Wilkinson, Paul Mooney and Harry Dutton. In his first season with the club, 1931-32, Harold made the League side just twice, and he had to continue his back-up role the following season when he played in a further four matches none of which was won before being released into non-League football in May 1933 at the age of 25.