Born in Worsbrough Bridge near Barnsley, Hardcastle made his professional debut at 8st 6lbs in May 1911, losing to Billy Green.
His next fight came two months later against Louis Ruddick for the Yorkshire flyweight title, Hardcastle retiring with a hand injury in the second round of twenty.
[1] Over the next three years he won most of his fights, mainly against novice boxers, and in December 1914 avenged his earlier defeat to Green to win the Pitmen's featherweight title.
After Llew Edwards vacated, Hardcastle faced former amateur champion Alf Wye in June for the British featherweight title.
[10][11] He successfully defended his British title in July against Ruddick, who was disqualified in the 15th round after hitting Hardcastle while he was down,[12][13] and in November made a second defence against Tancy Lee.