Dalston, Middlesex born inside right Harry Wilcox began his football career with Bromsgrove Rovers in 1896 and had a spell on the books of Aston Villa in 1897, playing only for their reserves, and a trial with West Hearts, the club that would become Watford, later the same year, before joining Second Division Small Heath in March 1898, making his Football League debut against Barnsley that September. A fringe player during his two seasons at Muntz Street, he scored 3 times in 17 appearances before joining Southern League Watford in July 1900, having a single season at Cassio Road during which he was a near ever present, scoring four goals in 32 appearances.
He was signed by Second Division Preston North End in June 1901, and was their top goalscorer in 1901-02 with 14 goals. netting a further 14 strikes in 1902-03. Many of his goals came from spot-kicks and led to him being nicknamed the ‘Penalty King’. In 1903-04 he managed 17 goals as Preston won the Second Division Championship, but he found opportunities limited once in the top flight, and he joined Southern League Plymouth Argyle in May 1905 after 45 goals in 109 appearances, 29 of which were penalties.
He missed just two games during his first season with Argyle, scoring 25 goals in 55 appearances. He was described as a “bold, dashing forward, possessing all the attributes necessary for the position”. Despite the success he moved on to Leicester Fosse in May 1906 with the 1906-07 Plymouth Argyle club handbook explaining that “efforts were made to retain him but the powers that be ruled that he longer belonged to Argyle”. The £75 transfer fee was paid by Leicester to Preston North End. After 16 goals in 45 appearances for The Fossils he joined West Bromwich Albion in November 1907, scoring 7 goals in 20 appearances for The Baggies during the rest of 1907-08.
He then returned to Plymouth Argyle in May 1908. His return coincided with the loss of central defender Charlie Clark and Wilcox was tried out in the middle of defence, a position he retained for the remainder of his career, the club handbook of 1911-12 stating that he was “second to none in the Southern League at centre-half”. He was also named as club captain in 1911, leading his side to the Southern League Championship in 1912-13, and he won many admirers for his courage on the pitch and sportsmanlike approach to the game.
Twice selected for The Southern League representative side, his career was effectively ended by the outbreak of the First World War, but not before he was awarded a well-deserved benefit game which took place on 18th March 1914. Wilcox did return to Home Park after working in Devonport Dockyard during the conflict, making four appearances for the club in 1919 before becoming player-coach of local Devon side Green Waves in 1920, having added 15 goals in 270 appearances to his previous total for Argyle.