[5][2] During a match against Aston Villa in September 1904, Hadley sustained a severe injury which put "grave doubt" on his ability to play again, following comments by a club director.
According to Holley & Chalk's "The Alphabet of the Saints" he was "a methodical yet energetic half-back, dedicated to looking after the forwards by supporting, feeding and directing them into advantageous positions".
[12] In November 1927 he took over at Aberdare Athletic, who had failed to gain re-election to the Football League the previous season.
His final managerial job was with Bangor City who he joined in July 1935[14] and left in April 1936 when he retired.
Hadley's brother Ben also played professionally for West Bromwich Albion, but had left before Harry's arrival at the Hawthorns.