Spinks is best known for defeating Muhammad Ali in February 1978 and becoming the new heavyweight world champion.
Spinks was then 24 years old and had only a handful of professional matches behind him.
- I do not think I was too young when I won.
Everyone who gets the opportunity I was given would take it, he said in 2003 according to ESPN.
Ali then took back the title in September of the same year, a victory that would prove to be Ali's last as a professional boxer.
Ended at 42 years old
Spinks tried to win back the WBC title in 1981, then from Larry Holmes, but lost.
He went down to cruiserweight and did not give up boxing until 1995, when he was 42 years old.
As an amateur, Spinks had, among other things, won Olympic gold in 1976, in light heavyweight.
In the same Olympics won, his little brother Michael Spinks took gold, in middleweight.
Sick of cancer
Leon Spinks suffered from cancer five years ago, a disease that took his life.
He was admitted to a hospital in Las Vegas in December last year, where he died on Friday.
"Hans fought in his last fight with the same skill, elegant style and fighting spirit that took him through so many of life's challenges," writes his spokesperson.