I think the most amazing thing about Ken Norton is that he had one of the least favorable paths to the top of the HW ranks.
He enlists into the Marine Corps after a few years of college in 1963 and within a year he takes an interest in the Marine boxing program. Now keep in mind that a military boxer is in many respects a step below a well trained amateur boxer in terms of time to devote to the sport and access to quality training/expertise. Norton rises to the top and he becomes a 3 time Marine HW champion by 1967.
He fulfills his military obligation in 1967 and he turns pro beginning the long hard climb of every boxer. He gradually acclimates to the professional game, and eventually serves as a sparing partner for the HW champion Joe Frazier. By the early '70s, at the age of 27, Norton is finally getting solid training under the guidance of the great Eddie Futch.
His big break comes 6 years after leaving the Marine corp, when at almost 30 years of age, with a mere 3 years of training under Futch, Norton finds himself ranked 8th in the HW division. He signs on to fight the No. 1 ranked Muhammad Ali in San Diego, March 31, 1973.
Before the fight, Ali predicts a 3rd round KO. But Norton doesnt read the script and the ex Marine dominates the ex-champ convincingly breaking Ali's jaw in a late round, likely the 12th. From that point on Norton is a household name. The rest is history.
He is one of the greatest raw talents to ever fight as a HW and anyone that has ever heard him speak can tell you that he was a great American a model citizen and a genuinely great man.