Shepherd, 76, “sadly passed away peacefully at his home last night”, his family have announced in a statement.
A pivotal figure in Newcastle’s rise during the 1990s, he was chairman for 10 years from 1997.
Shepherd eventually sold his share of the club to Mike Ashley and recently, along with brother Bruce, was granted the freedom of the city of Newcastle.
He was unable to deliver any major success to Newcastle, although he was responsible for bringing Geordie legend Alan Shearer “home” in 1996.
The former England striker joined in the tributes to Shepherd on Twitter.