Jeffries was born on April 15, 1875, in Carroll, Ohio, the son of Alexis C. Jeffries, a lay evangelist, and Rebecca Boyer Jeffries. In 1882 the family moved to California, where Alexis Jeffries became a successful farmer in East Los Angeles.
Although his family was relatively affluent, Jeffries worked as a boilermaker as a teenager and developed great strength in his upper body. Despite the opposition of his father, he supplemented his income by boxing. Jeffries easily defeated a number of opponents in California and built a local reputation. To sharpen his skills he arranged to spar with heavyweight champion James J. Corbett. In 1898 he journeyed to the East Coast and fought the black boxer Bob Armstrong. Although Jeffries won, he looked awkward and easy to hit. Bob Fitzsimmons, who had won the title from Corbett and was looking for an easy opponent, agreed to fight Jeffries. The bout took place on June 9, 1899, at Coney Island, in New York City. Jeffries outweighed the champion by almost forty pounds, but the experts expected Fitzsimmons' clever boxing to more than compensate for the weight difference. Unexpectedly, Jeffries fought from a crouch taught to him by boxer Tommy Ryan and neutralized most of his opponent's maneuvers. Although Fitzsimmons landed more punches, Jeffries' greater power began to have an effect, and in the eleventh round he knocked out the champion and won the title. Jeffries remained champion until 1905; his willingness to fight all challengers made him popular with the public. A natural athlete, he trained hard to improve his skills. He stayed in condition by running as many as fourteen miles a day, and he soaked his face in brine to reduce facial cuts during fights. Jeffries successfully defended his title six times. Several of the fights were difficult, and only his strength and stamina enabled him to win. His first defense was a twenty-five-round decision over Tom Sharkey in November 1899. Six months later former champion Corbett easily outboxed Jeffries for the first nineteen rounds, but became tired and was knocked out in the twenty-third round. In 1902 Jeffries won a rematch with Fitzsimmons. The former champion dominated the fight and by the eighth round had broken Jeffries' nose, but suddenly Jeffries swung twice and knocked Fitzsimmons out. A second successful defense against Corbett and victories over two lesser fighters left Jeffries with no challengers by late 1903. In 1905 Jeffries retired undefeated. Events persuaded him into one last fight, however. In 1908 an American black, Jack Johnson, won the heavyweight title. Race relations were worsening in the United States, and Johnson was extremely unpopular with white fans because he had married a white woman and openly refused to accept the segregated life required of American blacks. Pressure from the public and the guarantee of a large sum of money by George Lewis "Tex" Rickard, the most successful of the early boxing promoters, finally lured Jeffries back into the ring. The Johnson-Jeffries fight was a turning point in sports history. The bout was held on July 4, 1910, at Reno, Nevada, before nearly 20, 000 spectators. Johnson was in complete control and the referee stopped the fight in the fifteenth round, after Jeffries had been floored three times. Racists, unable to accept his defeat, circulated a story that he had been drugged. Jeffries denied this and cited as the cause of his defeat the fact that he had had to lose sixty-five pounds before the fight. This fight marked the merger of professional athletics and entertainment and the emergence of the modern sports business. Jeffries retired for good after the Johnson fight. Unlike many boxers, he proved to be a shrewd businessman, purchasing farmland in Burbank, California, and raising livestock. He also invested in the stock market, however, and was nearly bankrupted in the 1929 crash. Most of his losses were recovered through real estate transactions in the 1940's. Jeffries died in Burbank, on March 3, 1953.
Jeffries is generally regarded as one of the greatest heavyweight boxing champions. His size, strength, and endurance allowed him to wear down opponents and knock them out with a few powerful blows. His middle-class respectability improved the sport's image at a time when boxing faced formidable opposition. Ironically, Jeffries received more publicity and money for the one fight he lost than for any of his victories.
In 1904 Jeffries married Frieda.
