Leon Spinks celebrating his 15-round split decision victory over Muhammad Ali in Las Vegas – Photograph: AP

Bloomberg: MANHATTAN, New York – Leon Spinks, the heavyweight boxer who became undisputed world champion by upsetting Muhammad Ali in 1978 before losing a rematch only months later, has died. He was 67.

Spinks died on Friday, and had been suffering from prostrate and other cancers, the Associated Press reported, citing a press release.

Spinks was a 24-year-old unheralded boxer with just seven professional bouts before meeting Ali — 36 years old and in the twilight of his career — in Las Vegas on Feb. 15, 1978. The fight went the full 15 rounds and at the end, when Spinks won by a split decision, Ali’s face was badly bruised while Spinks looked fresh as he flashed his famous gap-toothed grin.

“I watched Ali fight for many years,” Spinks said in an interview with the Toronto Globe & Mail newspaper in 2011. “I had confidence I could beat the man.”

Ali clowned with the press the day before the fight by wearing false teeth and referring to Spinks as “Beaver,” mocking his opponent’s dental deficiencies. Ali said after his loss he hadn’t trained properly, was almost 20 pounds overweight and had underestimated Spinks’s stamina, allowing the challenger to pummel him on the ropes in the early rounds. He said fans needed to see Spinks defeat him twice before they would be convinced of the upset victory.

‘No Excuses’

“Leon Spinks is a good man,” Ali said in a 1978 television interview with Dick Cavett. “People have to give him credit because he won that night. I was a little off-guard, I make no excuses, but he won.”

Spinks’s reign as the World Boxing Association heavyweight champion lasted only seven months until his next fight, a rematch against Ali in the New Orleans Superdome for a purse of $3.75 million. He had been stripped of the World Boxing Council belt a month after winning the title because he agreed to a more lucrative rematch with Ali instead of fighting the No. 1 contender, Ken Norton.

Ali won the second fight, becoming the first to win the heavyweight crown three separate times.

Champion Brothers

Leon Spinks, right, connecting with a right hook to Muhammad Ali in 1978 during the late rounds of their first championship fight in Las Vegas, which Spinks won – Photograph: AP

Leon Spinks was the older brother of Michael Spinks, the International Boxing Federation belt holder who suffered the only defeat of his professional career when he was knocked out in the first round by Mike Tyson in 1988. The Spinks siblings were the first brothers to win heavyweight championships, an achievement that was matched two decades later by Wladimir and Vitali Klitschko.

In 1981, Leon Spinks had one more shot at the championship against Larry Holmes in Detroit’s Joe Louis Arena. After recovering from a knockdown, Spinks was cornered and pounded by Holmes in the third round when the referee stopped the fight just as the challenger’s corner threw in the towel. Spinks lost in a technical knockout. It was the last time he was a serious contender.

Leon Spinks Jr. was born on July 11, 1953, in St. Louis, according to the website Boxrec.com.

His parents, Leon Spinks Sr. and Kay Spinks, were separated when he was small, and he was raised, with six younger siblings, mainly by his mother in a public-housing project, according to a 1978 profile in the New York Times. He was so scrawny, his mother arranged for him to take boxing lessons so he could protect himself against bullies.

Olympic Gold

Spinks enlisted in the U.S. Marine Corps. He was a corporal when he won his Olympic gold medal fighting as a light heavyweight at the 1976 Olympics in Montreal. He and other U.S. medalist fighters — including Sugar Ray Leonard and Michael Spinks — were hailed in the media as an up-and-coming new generation for the sport.

After the 1981 Holmes bout, Spinks became more of a journeyman fighter than a potential champion, and he dropped to the cruiserweight division in later years. He retired in 1995 with a record of 26 wins, 17 losses and three draws, according to Boxrec.com.

There wasn’t much money left for him to enjoy. In 2005, he was “nearly broke” and working in Columbus, Nebraska, as a part-time janitor at a YMCA, according to an article published in the New York Times. He spoke of spending time in an East St. Louis, Illinois, homeless shelter. He was in the early stages of dementia.

In 2012, Spinks was diagnosed with shrinkage in the brain, the AP reported.

Spinks has a son, Cory Spinks, who was a welterweight and junior middleweight champion. Another son, Leon Calvin, who also fought professionally, was shot to death in 1990. A grandson, Leon Spinks III, fought as a lightweight.

  • Top Feature Photo: Leon Spinks battles Muhammad Ali during their second fight in the Louisiana Superdome on Sept 15, 1978 – Bettman/Getty Images