American boxer who was the world heavyweight champion from June 9, 1899, when he knocked out Bob Fitzsimmons (Fitzsimmons, Robert) in 11 rounds at Coney Island, New York City, until 1905, when he retired undefeated. Among his six successful title defenses were two knockouts of former champion James J. Corbett (Corbett, James J.) and a second victory over Fitzsimmons.

After several years in retirement, Jeffries was encouraged to make a comeback with the hope that he would be the white man,“the Great White Hope,” who could beat the first black heavyweight champion, Jack Johnson (Johnson, Jack). Jeffries attempted to regain the championship but was knocked out by Johnson in 15 rounds at Reno, Nevada, on July 4, 1910. Jeffries was inducted into Ring magazine's Boxing Hall of Fame in 1954.