Basingstoke, Hampshire born winger Sid Castle began his career with Basingstoke Town in 1913 and played for Thornycroft Athletic in 1914, prior to the First World War, during which he played as a wartime guest for Reading and Crystal Palace before joining Guildford City after the conflict’s resolution in August 1919. He was signed by Second Division Tottenham Hotspur from Guildford City in March 1920 and made his Football League debut at Stoke City in April, playing twice on their run in to their Second Division Championship. However he only played 3 more times for Spurs in the top flight before moving to Charlton Athletic in the summer of 1921.
He enjoyed two good seasons at The Valley, scoring 10 goals in 71 appearances before a return to the top flight when Chelsea signed him in the summer of 1923, and he went straight into a strong Chelsea line up that August. However he had lost his place early the following New Year and Chelsea went on to be relegated, thereafter he played only occasionally the following season, and after 2 goals in 32 games for Chelsea he returned to Guildford United in June 1926, before joining Weymouth the same September where he subsequently finished his playing career.
He then embarked on an extensive coaching career in Holland. In November 1927 he was appointed coach of Ajax, remaining till September 1928 when he took over as coach of ZAC, leaving in June 1930. The following month he became coach of PEC (now PEC Zwolle) and had two seasons with them before becoming coach of SC Heerenveen in 1932. In 1933 he became coach of Meppeler SC, staying until 1935 before returning to Heerenveen, coaching them between 1936 and 1938.