Midback "Jackie" Charlton was with, along with his brother Bobby Charlton, England's only World Cup gold ever, at home in 1966, and played throughout his active senior career for Leeds, 1952-1973.
He was also the national team captain for the Ireland men's team, 1986-1996, which he helped lead to the World Cup finals in both 1990 and 1994 and the 1988 European Championship.
About a year ago, Charlton was diagnosed with a type of lymph node cancer and he was also affected by dementia.
" LUFC is deeply saddened by the announcement that club legend Jack Charlton passed away last night, " the club writes on Twitter.
After his active career, Charlton stepped in as the national team captain for Ireland and took the national team to the World Cup finals in both 1990 and 1994.
Jack Charlton turned 85.
See pictures from Jack Charlton's football career in the video player above.