Andrew Wilson-Storey was taken to hospital after he was taken ill watching Rotherham United play Accrington Stanley last weekend.
The lifelong Millers fan, which the club has said "followed them up and down the country", died yesterday (Saturday) after a week in hospital in Lancashire.
A minute's silence was held in memory of Mr Wilson-Storey ahead of Rotherham's match later in the afternoon.
Tributes have been paid by the club, which described the news of his death as "heartbreaking".
A statement issued by the club said: "Rotherham United are extremely saddened to confirm that Andrew Wilson-Storey, who was taken seriously ill at the game against Accrington Stanley, has passed away.
"Andrew had been fighting bravely for his life in hospital in Lancashire since the incident last weekend with his family and friends by his side, but tragically lost his battle on Saturday morning.
"He was a lifelong Millers supporter who followed the club up and down the country, and following confirmation from his family, we are heartbroken to be reporting the news of his passing at such a young age."
The statement continued: "Everyone at Rotherham United would like to extend their sincere and heartfelt condolences to Andrew’s friends and family at this incredibly difficult time.
"We would also like to thank all of the medical staff who cared for Andrew both on the day of the incident and in hospital.
"The club will hold a minute's silence in Andrew's memory prior to kick off for the game with MK Dons. Rest in peace, Andrew."