Patterson vs. Moore

After beating Tommy "Hurricane" Jackson in an elimination fight, Patterson faced Light Heavyweight Champion Archie Moore on November 30, 1956, for the World Heavyweight Championship. He beat Moore by a knockout in five rounds and became the youngest World Heavyweight Champion in history, at the age of 21 years, 10 months, 3 weeks and 5 days. He was the first Olympic gold medalist to win a professional heavyweight title.

Patterson vs. Johansson I, II & III

After a series of defenses against fringe contenders (Hurricane Jackson, Pete Rademacher, Roy Harris,^[14] and Brian London), Patterson met Ingemar Johansson of Sweden, the number one contender, in the first of three fights. Johansson triumphed over Patterson on June 26, 1959, with the referee Ruby Goldstein stopping the fight in the third round after the Swede had knocked Patterson down seven times. Johansson became Sweden's first World Heavyweight Champion, thus becoming a national hero as the first European to defeat an American for the title since 1933.

Patterson knocked out Johansson in the fifth round of their rematch on June 20, 1960, to become the first man in history to regain the Undisputed World Heavyweight Championship. Johansson hit the canvas hard, seemingly out before he landed flat on his back. With glazed eyes, blood trickling from his mouth and his left foot quivering, he was counted out. Johansson lay unconscious for five minutes before he was helped onto a stool.

A third fight between them was held on March 13, 1961, and while Johansson put Patterson on the floor, Patterson retained his title by knockout in the sixth round to win the rubber match in which Patterson was decked twice and Johansson once, in the first round. Johansson had landed both right hands over Floyd's left jab. After getting up from the second knockdown, Floyd abandoned his jab and connected with a left hook that knocked down Johansson. After that, Patterson came on with a strong body attack that wore down Johansson. In the sixth round, Johansson caught Patterson with a solid right. But the power in Johansson's punches was gone. Patterson won the fight in the sixth round by knockout.^[15]

After the third Johansson fight, Patterson defended the title in Toronto on December 4 against Tom McNeeley and retained the title with a fourth-round knockout.^[16][17] However he did not fight number-one contender Sonny Liston. This was due in part to Cus D'Amato, who did not want Patterson in the ring with a boxer with mob connections. As a result, D'Amato turned down any challenges involving the IBC. Eventually, due to a monetary dispute with Jimmy Jacobs, Patterson removed D'Amato from handling his business affairs and agreed to fight Liston.

Patterson vs. Liston I & II

Leading up to the fight, Liston was the major betting-line favorite, though Sports Illustrated predicted that Patterson would win in 15 rounds. Jim Braddock, Jersey Joe Walcott, Ezzard Charles, Rocky Marciano and Ingemar Johansson picked Patterson to win. The fight also carried a number of social implications. Liston's connections with the mob were well known and the NAACP was concerned about having to deal with Liston's visibility as World Champion and had encouraged Patterson not to fight Liston, fearing that a Liston victory would tarnish the civil rights movement.^[18] Patterson said John F. Kennedy also did not want him to fight Liston.^[19]

Patterson lost his title to Liston in Chicago on September 25, 1962, by a first-round knockout in front of 18,894 fans. The two fighters were a marked contrast. In the ring, Liston's size and power proved too much for Patterson's guile and agility. However, Patterson did not use his speed to his benefit. According to Sports Illustrated writer Gilbert Rogin, Patterson did not punch enough and frequently tried to clinch with Liston. Liston battered Patterson with body shots and then shortened up and connected with two double hooks high on the head. The result at the time was the third-fastest knockout in boxing history.^[20] After being knocked out, Patterson left Comiskey Park in Chicago wearing dark glasses and a fake beard for the drive back to New York. After the fight, questions were raised on whether the fight was fixed to set up a more lucrative rematch. Overnight, Patterson seemed to lose his public support as a result of his swift knockout.^[21] Despite the defeat, Patterson won $2 million, to be paid over 17 years.^[22]

The rematch was set for April 1963; however, Liston injured his knee swinging a golf club and the fight was delayed three months to July 22. In Las Vegas that night, Patterson attempted to become the first boxer to win the heavyweight title three times, but Liston once again knocked him out in the first round. Patterson lasted four seconds longer than in the first bout. The Liston fights were the only times Patterson was actually counted out in his 20-year professional career.

Muhammad Ali

Patterson was now the number-one challenger for the title held by Muhammad Ali. On November 22, 1965, in Las Vegas, in yet another attempt to be the first to win the world heavyweight title three times, he went into the fight with an injured sacro­iliac joint which worsened after the first round and greatly reduced his mobility in a bout in which Ali was clearly dominant.^[24][25] Ali called Patterson an "Uncle Tom" for refusing to call him Muhammad Ali (Patterson continued to call him Cassius Clay) and for his outspokenness against black Muslims.^[26] Before the match, Patterson had said:

"This fight is a crusade to reclaim the title from the Black Muslims. As a Catholic, I am fighting Clay as a patriotic duty. I am going to return the crown to America."

Instead of scoring a quick knockout, Ali mocked, humiliated and punished Patterson throughout the fight but was unable to knock him out before the referee finally stopped the fight in the 12th round.^[27][28]

End of career

Patterson remained a legitimate contender. In 1966 he traveled to England and knocked out British boxer Henry Cooper in just four rounds at Wembley Stadium.

When Ali was stripped of his title for refusing induction into the military, the World Boxing Association staged an eight-man tournament to determine his successor. Patterson fought Jerry Quarry to a draw in 1967. In a rematch four months later, Patterson lost a controversial 12-round decision to Quarry. Subsequently, in a third and final attempt at winning the title a third time, Patterson lost a controversial 15-round referee's decision to Jimmy Ellis in Stockholm, in 1968, despite breaking Ellis's nose and scoring a disputed knockdown.

In September 1969 he divorced his first wife, Sandra Hicks Patterson, who wanted him to quit boxing, while he still had hopes for another title shot.

Patterson continued on, defeating Oscar Bonavena in a close fight over ten rounds in early 1972.

At age 37, Patterson was stopped after seven rounds with a cut eye while still competitive in a rematch with Muhammad Ali for the NABF heavyweight title on September 20, 1972.^[30] The defeat proved to be Patterson's last fight, although there was never an announcement of retirement.