Desperate for money, Dempsey would occasionally go into saloons and challenge for fights saying "I can't sing and I can't dance, but I can lick any SOB in the house." If anyone accepted his challenge, bets would be wagered. According to Dempsey's autobiography, he rarely lost these barroom brawls.
Dempsey's exact fight record is not known because sometimes he boxed under the pseudonym, "Kid Blackie." This practice continued until 1916. In between, he first appeared as "Jack Dempsey" in 1914, after an earlier middleweight boxer Jack (Nonpareil) Dempsey, drawing with Young Herman in six rounds. After that fight, he won six bouts in a row by knockout (as Jack Dempsey), before losing for the first time, on a disqualification in four rounds to Jack Downey. During this early part of his career, Dempsey campaigned in Utah frequently entering fights in towns up and down the Wasatch mountain range and keeping in shape with such sparring partners as Frank VanSickle day after day.
He followed his loss against Downey with a knockout win and two draws versus Johnny Sudenberg in Nevada. Three more wins and a draw followed and then he met Downey again, this time resulting in a four round draw.
Ten wins in a row followed, a streak during which he beat Sudenberg and was finally able to avenge his defeat at the hands of Downey, knocking him out in two. Then, three more non-decisions came (early in boxing, there were no judges to score a fight, so if a fight lasted the full distance, it was called a draw or non-decision, depending on the state or country the fight was being held in).
When the United States entered World War I in 1917, Dempsey worked in a shipyard while continuing to box. After the war, he was accused by some boxing fans of being a draft dodger. It was not until 1920 that he was able to clear his name on that account, when evidence was produced showing he had attempted to enlist in the U.S. Army but had been turned down.
Around this time Dempsey hooked up with Jack "Doc" Kearns, an experienced, clever fight manager who carefully and skillfully guided Dempsey to the top.
In 1918, Dempsey boxed 17 times, going 15–1 with one no decision. He avenged his defeat against Flynn by returning the favor, knocking him out in the first round. Among others he beat were light heavyweight champion Battling Levinsky, who had never been knocked out before Dempsey did so. Among others he beat were Bill Brennan, Fred Fulton, Carl Morris, Billy Miske ("newspaper decision") and Homer Smith.
He began 1919 winning five bouts in a row by knockout in the first round. Then on July 4, he and world heavyweight champion Jess Willard met at Toledo, Ohio, for the world title. Few gave Dempsey a chance against the larger champion and many called this fight a modern David and Goliath. Minutes before the fight started, Kearns informed Dempsey that he had wagered Dempsey's share of the purse on Dempsey winning with a first round knockout. As a result, the first round of the fight was one of the most brutal in boxing history. Dempsey dealt Willard a terrible beating and knocked him down seven times in the first round. Willard had a broken cheekbone, broken jaw, several teeth knocked out, partial hearing loss in one ear, and broken ribs. Kearns' own recollection of the event was the source of the loaded gloves' theory. The 20 January 1964 Sports Illustrated published an article interviewing Dempsey and Willard, on their recollections of the fight and of "Doc" Kearns. Kearns claimed he had applied plaster of paris to the customary wrappings under Dempsey's gloves, and that Dempsey did not seem to notice even when these reinforcements were removed after the fight. Dempsey never granted any credence to Kearns' story.
Under the rules at the time, a fighter was allowed to stand almost over a knocked-down opponent, and hit him again as soon as both knees had left the canvas. Several times Willard was knocked back down as he was trying to rise. Also, modern referees would step in to stop a fight if one of them was clearly defenseless, but the referee of this fight had the attitude that the only ending for a fight is an actual knockout. At the end of the third round the champion's handlers would not let him answer the bell for the fourth round. Although Dempsey had captured the Heavyweight Title, he never collected any money for the fight.
After beating Jess Willard and winning the title, Jack Dempsey traveled around the country, making publicity appearances with circuses, staging exhibitions, and even starring in a low-budget Hollywood movie. Dempsey did not defend his title until September 1920. This was against Billy Miske in Benton Harbor, Michigan. Miske was a good fighter but past his prime when he challenged Jack for the title, and was knocked out in 3 rounds.
Dempsey's second title defense was much tougher, against Bill Brennan in December 1920 at Madison Square Garden, New York City. Brennan had given Dempsey a tough match two years earlier. After 10 rounds, Brennan was actually ahead on points, and Dempsey's left ear was bleeding profusely. Dempsey rebounded to stop Brennan in the 12th round.
The next fight for "The Manassa Mauler" was against Frenchman Georges Carpentier, who had been a war hero during WWI and was extremely popular on both sides of the Atlantic. The bout was shrewdly promoted by Tex Rickard, emphasizing the differences between the two men, and George Bernard Shaw, who claimed that Carpentier was "the greatest boxer in the world" and stacked the odds 50 to 1 against Dempsey. The anticipation for this bout was tremendous.
Dempsey-Carpentier took place on July 2, 1921 at Boyle's Thirty Acres, Jersey City, New Jersey, generating the first million dollar gate in boxing history. A crowd of 91,000 watched the fight. Though it was deemed "the Fight of the Century," and Carpentier was favored 50 to 1, the match was not nearly as close as many assumed it would be. RCA arranged for live coverage of the match making the event the first national radio broadcast reaching mostly homemade radio sets after first being telegraphed to KDKA for broadcast.
Carpentier got off to a fast start and reportedly even wobbled Dempsey with a hard right in the 2nd round. A reporter at ringside, however, counted twenty-five punches from Dempsey in a single thirty-one second exchange soon after he was supposedly injured by the right. Carpentier also broke his thumb in that round, which crippled his chances. In the 3rd, the bigger, stronger Dempsey began to take charge and administered a brutal beating to Georges. The Frenchman was eventually stopped in the 4th round.
Dempsey did not defend his title again until July 1923 against Tommy Gibbons in Shelby, Montana. Gibbons was a skilled, clever boxer, but was not powerful enough against the bigger, stronger Dempsey, who won a 15 round decision.
The last successful title defense for Dempsey was in September 1923 at New York's Polo Grounds. The opponent was the huge, powerful, yet limited contender Luis Angel Firpo, from Argentina. Attendance was 85,000, with another 20,000 trying to get inside the arena. Dempsey won via a 2nd round KO, but it was an exciting battle. Firpo was knocked down repeatedly yet continued to battle back, even knocking Dempsey down twice. The second time Dempsey was floored he went sailing head first through the ring ropes, landing on a reporter's typewriter, and taking several more seconds than the ten stipulated by the rules. This scene is one of the most memorable in sports history. (This fight was so important that it was transmitted live to Buenos Aires by radio, and people gathered in the streets to listen to it through primitive amplifiers.)
These fights, plus his many exhibitions, movies and endorsements, had made Dempsey one of the richest athletes in the world.
After the Firpo brawl, Dempsey did not defend his title for another 3 years. There was pressure from the public and the media for Dempsey to defend his title against black contender Harry Wills. Politics and racial fears prevented the Dempsey-Wills bout. There is disagreement among boxing historians as to whether Dempsey avoided Wills. Dempsey always claimed he was willing. Instead of defending his title, Dempsey continued to earn money by boxing exhibitions, making movies and endorsing products. Dempsey also did a lot of traveling, spending and partying. During this time away from competitive fighting, Dempsey married actress Estelle Taylor, and broke up with his long-time trainer/manager Jack "Doc" Kearns. This break-up did not go smoothly, and Kearns repeatedly sued Dempsey for huge sums of money.
In a big upset, Dempsey lost his title on points in ten rounds. No longer displaying his legendary punching power or hand speed, Dempsey was easily outboxed by the slick Tunney who would dodge, and then let loose with a salvo of punches of his own. The attendance for this fight was a record 120,557, the second largest attendance ever for a non-automobile sporting event (the 1950 soccer world cup finals between Brazil and Uruguay had 150,000+ spectators). When the battered Dempsey returned to his dressing room, he explained the defeat to his film actress wife Estelle Taylor by saying, "Honey, I forgot to duck." This phrase was later used by President Ronald Reagan to his wife after Reagan was shot during a failed attempt on his life in 1981.
Dempsey contemplated retiring, but after a few months of rest decided to try a comeback. In July 1927, at Yankee Stadium, he knocked out future heavyweight champion Jack Sharkey in the seventh round of an elimination bout for a title shot against Tunney. Sharkey was beating Dempsey until the end, when the fight ended controversially. Dempsey had been hitting Sharkey below the belt, and Sharkey turned to the referee to complain, leaving himself unprotected. Dempsey took advantage and crashed a left hook onto Sharkey's chin, knocking him out cold. The referee then counted out Sharkey.
The Tunney rematch took place in Chicago, Illinois, on September 22, 364 days after losing his title to Tunney in their first bout. This fight generated even more interest than the Carpentier and Firpo bouts, generating an amazing 2 million dollar gate, a record that stood for many years.It is said that Al Capone offered Dempsey that he could fix the rematch, but he would not hear of it. Millions of people around the country listened to the bout on the radio, and hundreds of reporters covered the event. Tunney was paid a record one million dollars for the Dempsey rematch. Dempsey earned about half that.
Dempsey was losing the fight on points when he knocked Tunney down with a left hook to the chin in the seventh round, and landed several more punches. A new rule for boxing at the time mandated that when a fighter knocks down an opponent, he must immediately go to a neutral corner. But Dempsey seemed to have forgotten that rule (compare his fight with Willard where he almost stood over his downed opponent ready to strike again) and refused to immediately move to the neutral corner when instructed by the referee. The referee had to escort Dempsey to the neutral corner, which bought Tunney at least an extra five seconds to recover.
The official timekeeper for the fight counted the time Tunney stayed down as 14 seconds. But, after Dempsey finally went to a neutral corner, the referee started his count, and Tunney got up at the referee's count of nine. Dempsey tried to finish Tunney off before the round ended, but he failed to do so. A fully recovered Tunney dropped Dempsey for a count of one in round eight, easily won the final two rounds of the fight, and retained the title on a unanimous decision. Ironically, the new rule (which was not yet universal) was requested during negotiations by members of the Dempsey camp. Another discrepancy was the fact that when Tunney knocked Dempsey down, the referee started the count immediately, not waiting for Tunney to move to a neutral corner. Because of the controversial nature of the fight, it remains known in history as the fight of "The Long Count."
When the United States entered World War II, Dempsey had an opportunity to refute any remaining criticism of his war record of two decades earlier. He volunteered for national service and was commissioned as a commander in the U.S. Coast Guard, charged with developing a physical fitness program for U.S. soldiers. Later, he served as a morale officer in the Pacific and in 1945 became a hero to many when, at age 49, he insisted on going into battle on Okinawa with a group of men he had trained.
Dempsey wrote a book on boxing, Championship Fighting: Explosive Punching and Aggressive Defense, which was published in 1950. Dempsey was also something of a cross-trainer, he wrestled in training camp and later took judo lessons. He later wrote a book on this, How to Fight Tough, which dealt with close-quarters combat incorporating boxing, wrestling, and jiu-jitsu.
He made friends with Wills and Tunney after retirement, and had many books written about his life. Dempsey even campaigned for Tunney's son John when he ran for the U.S. Senate, from California. One of Dempsey's best friends was Judge John Sirica who presided over the Watergate trials.
In 1977, in collaboration with his stepdaughter Barbara, Jack published his autobiography, titled Dempsey. In May 1983, Dempsey died of natural causes at age 87. His wife Deanna at his side, he told her..."Don't worry honey, I'm too mean to die." He is buried in the Southampton Cemetery, Southampton, New York.
Dempsey is a member of the International Boxing Hall Of Fame. The street where Madison Square Garden is located is called Jack Dempsey Corner.