Born in Boston in 1858 to Irish Immigrants.Sullivan was nicknamed The Boston Strongboy. As a youth he was arrested several times for participating in bouts where the sport was outlawed, and he went on exhibition tours offering people money to fight him. In 1879, he challenged anyone in America to fight him for $500.
In 1883 - 1884 Sullivan went on a coast-to-coast tour by train with five other boxers. It was scheduled to comprise 195 performances in 136 different cities and towns over 238 days. To help promote the tour, Sullivan announced that he would box anyone at any time during the tour under the Queensberry Rules for $250. He knocked out eleven men during the tour.
In Sullivan's era, no formal boxing titles existed. He became a champion after defeating Paddy Ryan in Mississippi City, near Gulfport, Mississippi on February 7, 1882. Modern authorities have retroactively labelled Ryan the "Heavyweight Champion of America", but he could certainly be considered as much a "world champion" as Sullivan. Depending on the modern authority, Sullivan was first considered world heavyweight champion either in 1888 when he fought Charley Mitchell in France, or the following year when he knocked out Jake Kilrain in round 75 of a scheduled 80-round bout. But in truth, neither match was considered at the time to be about determining a world heavyweight champion.
When the modern authorities talk of the heavyweight championship of the world, they are probably referring to the championship belt presented to Sullivan in Boston on August 8, 1887. The belt was inscribed Presented to the Champion of Champions, John L. Sullivan, by the Citizens of the United States. Its centerpiece featured the flags of the US, Ireland, and the United Kingdom.
Mitchell came from Birmingham, England and fought Sullivan in 1883, knocking him down in the first round. Their second meeting took place in 1888 on the grounds of a chateau at Chantilly, France in driving rain. It went on for more than two hours, at the end of which both men were unrecognisable and had suffered much loss of blood; neither could lift his arms to punch and the contest was considered a draw.
The local gendarmerie arrived at this point and managed to arrest Mitchell, who spent the next few days in a cell and was later fined by the local magistrate, boxing being illegal in France at that time. Sullivan managed to evade the law, swathed in bandages, and was taken back across the English Channel to spend the next few weeks convalescing in Liverpool. Mitchell acted as Sullivan's corner man for many years after.
Undefeated at that point, Sullivan did not defend his title for the next four years. During this time he famously refused to fight Commonwealth champion boxer Peter Jackson, because he was black. He agreed to defend his title in 1892, losing to "Gentleman Jim" Corbett in 21 rounds. Corbett was younger, faster and his boxing technique enabled him to dodge Sullivan's crouch and rush style. The heavyweight contest occurred under the Marquess of Queensberry rules, but it was neither the first title fight under those rules nor was it the first title fight using boxing gloves.
Sullivan is considered the last bare-knuckle champion because no champion after him fought bare-knuckled. However, Sullivan had fought with gloves under the Marquess of Queensberry rules as early as 1880 and he only fought bare knuckle three times in his entire career (Ryan 1882, Mitchell 1888, and Kilrain 1889). His bare-knuckle image was created because both his infrequent fights from 1888 up to the Corbett fight in 1892 had been bare-knuckle.
Sullivan retired to Abington but appeared in several exhibitions over the next 12 years, including a three-rounder against Tom Sharkey and a final two-rounder against Jim McCormick in 1905. He continued his various careers outside boxing such as stage actor, speaker, celebrity baseball umpire, sports reporter, and bar owner.
In his later years Sullivan became a teetotaler and often supported the temperance movement. He died of health problems caused by his earlier alcoholism, aged 59, and is buried in the Old Calvary Cemetery in Mattapan, now a neighborhood of Boston.