James John Corbett (September 1, 1866 – February 18, 1933) was an American heavyweight champion whose intelligence, technique, and ring composure forever changed the sport. Known to history as “Gentleman Jim,” he is celebrated as the man who defeated the legendary John L. Sullivan in 1892, signaling the dawn of modern boxing.

Born in San Francisco to Irish immigrants from County Mayo, Corbett’s sharp mind and refined manner earned him his famous nickname. He stood 6 feet 1 inch tall and combined agility, strategy, and precise punching in a way the sport had never seen. At a time when brute force defined the heavyweight ranks, Corbett’s emphasis on movement, timing, and defensive craft earned him the title “Father of Modern Boxing.”

Corbett’s rise began at San Francisco’s Olympic Club, where he both trained and coached. In 1891, he fought the highly respected Peter Jackson to a 61-round no-contest—an exhausting display of endurance and skill that elevated his national profile. The following year, he challenged reigning champion John L. Sullivan at the Olympic Club in New Orleans. Using footwork and calculated precision to outthink the charging Sullivan, Corbett scored a knockout in the 21st round, becoming the new World Heavyweight Champion and ushering in a new era governed by science and finesse rather than brawling.

Corbett defended his title successfully once, stopping England’s Charley Mitchell in three rounds in 1894. That same year, he made history again when his exhibition bout with Peter Courtney was filmed at Thomas Edison’s Black Maria Studio—one of the world’s first recorded boxing matches.

In 1897, Corbett lost his title to Bob Fitzsimmons in Carson City, Nevada, in a fight immortalized on film as The Corbett-Fitzsimmons Fight. Despite outboxing Fitzsimmons early, Corbett was stopped by a single devastating body blow in the 14th round. It was the first recorded knockout ever seen on film.

Corbett continued to fight top contenders, including two classic encounters with James J. Jeffries. His near-upset against Jeffries in 1900 is often cited as one of the most courageous performances in boxing history, as Corbett, giving up both youth and size, led on points before being stopped in the 23rd round.

Beyond the ring, Corbett’s charm and intelligence carried him to the stage, where he enjoyed a successful career in theater. He also remained active in the sport as a coach and public speaker, representing the dignity and class that earned him his enduring nickname.

James J. Corbett passed away in 1933, leaving behind not only a championship legacy but a technical blueprint that shaped every great boxer who followed. His influence marked the transition from the bare-knuckle era to the gloved age, cementing his place as one of the most significant figures in boxing history.