Ironside was born in Middlesbrough in the north of England, and is the son of the former goalkeeper for Scarborough F.C., Ian Ironside. Joe signed a professional contract at Sheffield United F.C. in the summer of 2012 after his performance for the under-18 side in the FA Youth Cup. The team reached the final against the Manchester United F.C. under-18s at Old Trafford, a game in which Ironside scored.