(CNN) -- Forty years after rising to the top of the boxing world and outdueling Muhammad Ali, Ken Norton lost his final fight -- a battle following a stroke -- at a Nevada medical facility, a friend said.
He was 70 years old when he died Wednesday at a Veterans Affairs' medical facility in Henderson, Nevada, according to Gene Kilroy, who had managed Ali and more recently visited Norton as he recovered from a stroke.
While some younger people may know him best as the father of former Dallas Cowboys and San Francisco 49ers linebacker Ken Norton Jr., the elder Norton was one of the most prominent figures in all of sports during the 1970s -- in large part because of his consistently great bouts with Ali.
Their first showdown, in 1973, ended with Norton earning a split-decision victory -- and breaking Ali's jaw in the process. But Ali got his revenge six months later, winning their rematch in another split decision.
The two fighters faced off one more time in 1976 at New York's Yankee Stadium, with Ali again taking the win in what Norton's website calls "a highly disputed split decision."
Well before he became Ali's archrival, Kenneth Howard Norton established himself as a standout athlete. Raised in small central Illinois city of Jacksonville, Norton earned a football, basketball and track scholarship to Northeast Missouri State College.
Norton didn't begin boxing until being introduced to the sport while serving in the Marines Corps between 1963 and 1967. There, he soon flashed his talent in the ring en route to becoming a three-time All-Marine Heavyweight Champion, according to the Marine Corps Sports Hall of Fame, which inducted Norton into its 2004 class. He also earned a North Carolina Golden Gloves, International AAU and Pan American titles while still in the service.
The year he left, in 1967, Norton went pro. It took him six more years to get a shot at a championship against Ali, and he won.
While he lost that title back to Ali later the same year, a first-round knockout of Duane Bobick earned Norton the honor of being champ again in 1977. That same year, the Boxing Writers Association of America named Norton its Fighter of the Year.
Still, that championship also proved short-lived after Norton lost a grueling 15-round fight to Larry Holmes. He retired from boxing in 1981 after amassing a professional record of 42 wins (including 33 knockouts), seven losses and one draw.
The International Boxing Hall of Fame inducted Norton in 1992, hailing him as "a fixture in the heavyweight ranks during a time that many consider the finest era of the division." His profile on the hall's websites notes Norton "possessed an awkward and powerful style and always entered the ring in great condition."
One of the other elite fighters of the era, George Foreman, said upon news of Norton's death that Norton deserved his spot in the upper echelon of the sport.
"They called us all handsome," Foreman tweeted. "Muhammad they called pretty. But The fairest of them all Ken Norton."
Yet he was more than a boxer. Starting with Dino De Laurentis' film "Mandingo," Norton appeared in about 20 movies. He also fathered five children, including his namesake, now a linebackers coach with the NFL's Seattle Seahawks.
Norton also became close friends with Ali, whom he visited in the hospital the day after their first bout. According to Kilroy, Ali told Norton, "You hit so hard."
His website also notes that Norton was once counted out before: in 1986, when he refused to accept a doctor's prognosis he wouldn't be able to walk or talk again after a serious accident.
"At first they thought I might die, and if I didn't die, I wouldn't be coherent," he said later. "Now I'm talkin' and walkin' and I can even chew gum at the same time."
His more recent health crisis, a stroke, left him communicating by blinking his eyes, Kilroy recalled. Still, the former Ali manager said there was a lot of laughter in the room during Kilroy's visit along with other legendary boxers Mike Tyson, Earnie Shavers and Thomas Hearns.
"Now that he's gone, he has no pain," Kilroy said. "He's sitting up there in the heavens right now talking with the other greats like Joe Louis."
Beyond touting Norton the boxer, Tyson on Wednesday remembered him first as "a great man" who was "always nice to me even when I was an amateur fighter."
"He always treated me like I was somebody," Tyson tweeted."Remarkable man."
CNN's Amanda Watts contributed to this report.
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