With a nickname like “Cinderella Man,” James J. Braddock was the original sports underdog. Unlike others on this list, Braddock had a quick start to his pro sports career, going 44-2-2 as a light heavyweight. But when he finally got his shot at the title against Tommy Loughran in 1929, Braddock lost the match in 15 rounds, and took his anger out on his poor right hand—fracturing it in multiple places. Braddock then fell into a deep depression, which wasn’t made any easier by the actual Depression. After losing 20 of his next 33 fights, Braddock hung up his gloves and started working as a longshoreman, also collecting welfare to support his family.
While his boxing career seemed all but kaput, he was given a fight opportunity in 1934, and worked his way up to a heavyweight title bout with Max Baer. A 10-1 underdog, nobody gave Braddock a shot, and Baer infamously refused to train for the fight. The elder Braddock (30) showed no quit, however, against Bear (26) and won the Heavyweight Championship.