5. James J. Jeffries
The behemoth from Burbank has just 22 fights on his official record, though it’s safe to assume he fought plenty more times than that. The burly heavyweight knocked out the highly-touted Hank Griffin in just his third fight before fighting top contender Gus Ruhlin to a draw – though some observers feel Jeffries deserved the nod. A third-round stoppage win over Peter Jackson in 1898 threw him into the title mix, as did a 20 round decision win over Tom Sharkey.
The next year he got his crack at reigning champion Bob Fitzsimmons. Scheduled for 20, Jeffries stopped Fitzsimmons in the 11th to lift the title. He held on to the title for five years, beating the likes of James J. Corbett (twice), Fitzsimmons again and Jack Munroe. Jim took a beating in his rematch with Fitzsimmons, but somehow fought through the blood seeping from his face to finish Bob with a monstrous left hook.
He retired in 1904, going out on top. However, it would be time that proved to be Jeffries’ undoing. He returned to the ring in 1910, having bloated in weight in the interim. His opponent – world heavyweight champion Jack Johnson. Jim whipped himself into terrific shape but was outclassed in the bout, being stopped in the 15th of a scheduled 45(!).