One of an estimated 500 former football professionals to be diagnosed with dementia, Mike Sutton has died aged 76.
During a decade-long sporting career, he made more than 250 appearances for Norwich, Chester and Carlisle United in the 1960s and 70s.
After hanging up his boots, he became a PE teacher then returned to the field with Great Yarmouth Town. He was also involved in his local cricket club.
His son Chris, a football pundit and former Celtic and Norwich player, paid tribute via social media on Sunday.
He tweeted: “My dad Mike sadly passed away yesterday.
“He was a great sportsman, teacher, husband, dad and grandad. He was my hero and I will miss him so much.”
Sutton began his playing career in his home city of Norwich, making his first professional appearance in 1962.
After more than 50 appearances in five years, he transferred to Chester where he played in 138 matches.
He moved to Carlisle in 1970 but retired two years later due to a knee injury.
Sutton then retrained in physical education and biology to become a high school teacher.
Later, he returned to the pitch for a spell at Great Yarmouth Town and as a youth coach at Norwich.
Sutton was diagnosed with dementia in 2010, a year after he retired, when family members began to notice changes in his behaviour.
In recent years he required round-the-clock care, and his son Chris has been a prominent voice in the fight to get former players better support.
Campaigners have been calling for further research into links between heading a football and developing brain conditions such as dementia, as well as restrictions on how often it can be performed during training.
Chris Sutton previously told The Daily Mail: “It wipes you out as a person and leaves a blank page.
“My dad and countless others have been let down.”
Tributes to Mike Sutton from across the sporting world were shared online following his death on Boxing Day.
Pundits Simon Thomas, Eilidh Barbour and Gary Lineker were among those sharing their condolences.
Former Manchester United star Rio Ferdinand said: “Sorry to hear this Chris. Continue raising the awareness.”
And Football Focus host Dan Walker wrote: “Really sorry to hear about your dad Chris.
“I know you have been valiantly fighting his corner for a long time.”
Carlisle United chairman Andrew Jenkins said: “Mike was a quiet, humble and extremely likeable man who did his job in an efficient and professional manner.
“He really looked after himself and he had a very forward looking attitude.
“In fact, he was one of the first to insist on a vegetarian style pre-match meal when the other lads would be having the traditional choice of a steak.
“He was respected by his fellow professionals for his approach and was a man others would look to for advice, and it was no surprise when he went into teaching and lecturing as his second career.”