Corbett began boxing as an amateur when he was eighteen and within a year he won the championship of San Francisco's Olympic Athletic Club, which produced some fine fighters. Among them was Joe Choynski, a challenging stepping stone to the heavyweight title.
Using the name "Joe Dillon" to avoid losing his amateur status, Corbett fought professionals in Utah and Wyoming before returning to California in 1889 for three fights against Choynski. Corbett won two of them, one by knockout, and the third was stopped by the police after four rounds.
On May 21, 1891, Corbett fought Peter Jackson, an Australian who couldn't get a championship fight against the reigning John L. Sullivan because he was black. The match went 61 rounds before it was declared no contest because both boxers were too exhausted to continue.
Corbett met Sullivan on September 7, 1892, in New Orleans in the first championship fight using padded gloves under the Marquis of Queensbury Rules. He won the title by knocking Sullivan out in the 21st round.
The popular, dapper Corbett spent much of the rest of his career capitalizing on his championship without much fighting. He appeared in Broadway shows, fought an exhibition for the first boxing movie at Thomas Edison's laboratory, and toured England triumphantly after his first title defense, a 3-round knockout of Charley Mitchell on January 25, 1894.
Corbett lost the championship when Bob Fitzsimmons knocked him out in the 14th round on March 17, 1897, in Carson City, NV. He twice tried to regain the title against James J. Jeffries, but was knocked out both times, in the 23rd round on May 11, 1900, and in the 10th round on August 14, 1903.
"Gentleman Jim" is generally considered the first really scientific fighter because he used speed and knowledge of his opponent's strengths and weaknesses to develop a strategy for a fight, rather than depending on brawn and sheer volume of punches. He fought only 19 professionals bouts, winning 11, 7 by knockout, and losing 4, 3 by knockout. He also had 2 draws and 2 no-contests.
