Jeffries was born on April 15, 1875 at Carroll, Ohio. He was the son of Alexis Jeffries, a farmer and minister, and Rebecca Boyer Jeffries. Jim had four brothers and three sisters. In 1881, the family moved to Los Angeles.
Jeffries was a clean-cut man of high moral and ethical standards and fair to all people.
He has been branded incorrectly as a racist because he came out of retirement to fight Jack Johnson and was labeled as the "Great White Hope" by sportswriters. It is often pointed out that he only fought White contenders for the title. But, all the champions at that time did so.
Even Jack Johnson drew the "color line" when he became Champion. The only black man he fought for the title was Jim Johnson, a mediocre boxer, when he was in Europe and needed funds.
As a youth, Jim became involved with wrestling and boxing but put off his career at the request of his mother and father.
Jeffries stood 6-2 1/2 in his fighting prime and in top condition weighed between 206-227 lbs. When not in top condition, Jeffries weighed between 250-280 lbs.
His fight manager was William Brady. There was never a legal contract between the men, simply a handshake. Brady said Jeffries' word was better than a contract.
His trainer for most of his career was Billy Delaney.
Jeffries could run 100 yards in a little more than ten seconds. He could high jump over six feet. Blessed with abnormal physical strength, he was considered a natural phenomenon.
A lover of hunting, he once killed a large deer and carried it on his shoulders nine miles to camp without stopping to rest. Friends who accompanied him had difficulty keeping up with him on the jaunt home.
He married in 1904. He and his wife, Freida, had one daughter, Mary.
In his later years, he trained a few boxers and promoted some fights at Jeffries' Barn.
He was well-liked, spent time with the local people, attended gatherings, and contributed much to his community.
Jeff died in his sleep on March 3, 1953 at Burbank, California.