American Bob Hayes, who won the 100m sprint at the 1964 Olympics in Tokyo, died in Florida late last night.
His daughter reported that the 59-year-old may have died from kidney failure however the precise cause of death which followed a long battle against ill health was unclear.
Hayes, who was born on December 20, 1942, was admitted to hospital last December in a critical condition with acute flu after fighting illnesses including heart and liver problems, and prostate cancer.
Once considered the fastest man alive, who went on to find Super Bowl success in American football, Hayes spent his final days in hospital and his life, after a sparkling sports career, was often besieged by alcohol and drug problems. In 1979 he spent time in prison after providing an undercover drugs officer with narcotics.
However, despite never being enshrined in the NFL's Hall of Fame - mainly due to his off-field weaknesses - Hayes will still be remembered as the one-time 'fastest human on earth'.
"Bob was one of the greatest athletes of all time," recalled Ollan Cassell, a member of the same American team as Hayes in Tokyo.
"He was a giant in two sports," added Cassell, who went on to become an executive director of the American athletics' federation.
Hayes made his name after sweeping the field aside in style at the 1964 Olympics in both the 100m and as part of the triumphant 4x100m relay team.
Running in lane one in the 100m final, he came home a full two metres ahead of his closest rivals, Cuba's Enrique Figuerola and Canada's Harry Jerome who came second and third respectively.
In winning gold Hayes equalled German Armin Hary's world record (electronically-timed) of 10.05sec. According to the hand-held times, Hayes ran in 9.9 seconds.
More sensationally, while the American relay team were being led in the final, Hayes anchored the team to victory.
He was also the first black athlete to end the domination of white sprinters - since Harrison Dillard in London 1948, no black athlete had been successful in the Olympic 100m.
However shortly after his Olympics success Hayes announced his retirement from athletics at the age of 22 and played with the Dallas Cowboys football team.