Joe Frazier, a onetime heavyweight champion whose epic battles with Muhammad Ali in the 1970s spilled from the boxing ring into a decades-long war of words, died Nov. 7 of liver cancer at age 67.

His family said he died in hospice care in Philadelphia.

Mr. Frazier and Ali were the dominant heavyweights of their generation, and their rivalry was considered one of the most heated and enduring in all of sports. Both fighters had won Olympic gold medals, but in most other respects they were very different.

Mr. Frazier, a sharecropper’s son from South Carolina, was stocky and powerful. The most exciting thing about him was his nickname, “Smokin’ Joe.” His crouching, relentless style of boxing was in stark contrast to the tall, graceful presence of Ali. Even more telling, Mr. Frazier’s quiet stoicism was no match for Ali’s glib flamboyance.

The last of their three fights, the “Thrilla in Manila” in 1975, is widely ranked as the greatest match in boxing history.

But the bouts that Mr. Frazier and Ali fought in the ring were complicated by a personal antipathy rare in sports. Ali’s needling of Mr. Frazier turned from ordinary ribbing to something deeper that reflected the divisions of race and opportunity in America.

Ali had been the heavyweight champion from 1964 to 1967, when he had to relinquish his title after refusing to participate in the military draft.

In 1970, Mr. Frazier beat Jimmy Ellis to become the undisputed heavyweight champion. With Ali returning to boxing after a three-year layoff, the stage was set for a showdown.

Against a background of political and racial upheaval, Ali called Mr. Frazier “ignorant,” “dumb” and an “Uncle Tom.”

Mr. Frazier, who had admired Ali, was baffled and insulted by what he considered a betrayal of the brotherhood of boxers. In response, he referred to Ali by his original name of Cassius Clay, which Ali considered an affront.

“Clay, he makes me laugh,” Mr. Frazier told Sports Illustrated in 1971. “What do he know about hard times? Bigmouthing and loud talk, he’s an expert on that, but hard times — that’s something else.”

Their first fight took place at New York’s Madison Square Garden on March 8, 1971, with a glittering backdrop. The crowd was studded with celebrities, including Woody Allen, Dustin Hoffman and Diana Ross. Frank Sinatra was a ringside photographer for Life magazine. Each fighter was guaranteed $2.5 million, the highest purse in boxing history at the time.

Early in the fight, Ali shook his head in disdain whenever Mr. Frazier caught him with a punch. By the 11th round, Ali was reeling backward from a succession of blows. For the first time, he looked confused and defeated in the boxing ring.

About 25 seconds into the 15th and final round, Mr. Frazier landed a left hook on Ali’s jaw, sending him to the floor, with his head bouncing off the canvas.

Mr. Frazier won a unanimous decision, giving Ali the first loss of his career. Both fighters ended up in a hospital.

On Jan. 22, 1973, Mr. Frazier lost his title when George Foreman knocked him down six times in two rounds, prompting ABC broadcaster Howard Cosell’s memorable exclamation: “Down goes Frazier! Down goes Frazier! Down goes Frazier!”

Mr. Frazier and Ali met in January 1974 in a lackluster non-title fight that Ali won by decision. That October, in the fight that was known as the “Rumble in the Jungle,” Ali reclaimed his championship by defeating Foreman with an eighth-round knockout in Zaire.

Ali and Frazier met again on Oct. 1, 1975, in the Philippines.

Before the fight, Ali sharpened his rhetoric into venomous psychological warfare. He corrected Mr. Frazier’s speech at news conferences, called him a “gorilla” and pulled a small rubber gorilla from his pocket for the cameras.

The fight took place in extremely hot conditions. Seemingly with each punch, the sweating crowd switched its allegiance from one boxer to the other.

In the sixth round, Mr. Frazier knocked out Ali’s mouthpiece.

“They told me you was washed up!” Ali shouted.

“They lied,” Mr. Frazier replied.

In the 10th round, Ali found new reserves of strength and began to assault Mr. Frazier with combinations of punches. In 13th round, he sent Mr. Frazier’s mouthpiece flying into the fourth row of the crowd.

After the 14th round, in which Mr. Frazier absorbed more than 30 blows to the head, the referee had to lead him to his corner. Both of Mr. Frazier’s eyes were swollen almost completely shut. His trainer told the referee, over Mr. Frazier’s protest, to end the fight.

During the bout, Mr. Frazier landed more than 440 punches on Ali.

“I hit him with punches that bring down the walls of a city,” he said. “What held him up?”

“It’s the closest I’ve come to death,” Ali said.

After the fight, Mr. Frazier’s son Marvis, who later had a notable boxing career, visited Ali’s dressing room.

“Tell your dad the things I said I really didn’t mean,” Ali said.

“He should come to me, son,” Mr. Frazier said. “He should say it to my face.”

Joseph William Frazier was born Jan. 17, 1944, in Beaufort, S.C., one of 13 children. He showed an early interest in boxing and pounded a heavy bag he hung from a tree.

He left home at 15 and began an amateur boxing career in Philadelphia. In 1964, he won an Olympic gold medal in Tokyo, despite fighting with a broken thumb. He turned professional the next year.

He lost only four times in 37 professional fights — twice each to Ali and Foreman.

For several years, Mr. Frazier led an R&B group called Smokin’ Joe and the Knockouts. In later years, he ran a boxing gym in Philadelphia.

His marriage to Florence Smith ended in divorce. He had at least 11 children with various women. A complete list of survivors could not be confirmed.

For years, Mr. Frazier refused to forgive Ali for his insulting behavior. In 1996, when Ali, trembling from Parkinson’s syndrome, struggled to light the Olympic torch in Atlanta, a still-seething Mr. Frazier said, “It would have been a good thing if he would have lit the torch and fallen in. If I had the chance, I would have pushed him in.”

Only after a formal apology from Ali in 2001, did Mr. Frazier lay their enmity to rest.

He was champion for only three years, but Mr. Frazier is remembered as one of the most valiant boxers in history. As he struggled back to his corner after the 14th round of the “Thrilla in Manila,” Mr. Frazier’s trainer, Eddie Futch, told him, “The fight’s over, Joe.”

Mr. Frazier leaped to his feet, saying, “Eddie!”

“Sit down, son,” Futch said. “It’s over.”

“You can’t do that to me,” Mr. Frazier pleaded.

Refusing to let the fight continue, Futch said, “No one will forget what you did here today.”