A few days before Super Bowl X in 1976, some of the N.F.L.’s biggest stars mingled at a private party at a nightclub in Miami. Chuck Foreman, then a fearsome running back with the Minnesota Vikings, remembered rubbing shoulders with some of the biggest stars of the time at the position, including Walter Payton and O.J. Simpson.

Then he sat down with Jim Brown, the greatest running back of them all, who had left the Cleveland Browns a decade before. Foreman, who rolled over linebackers and cornerbacks for a living, recalled that he was intimidated. He grew up idolizing Brown not just for his prowess on the field, but for his willingness to fight for civil rights and to walk away from the game at the peak of his powers.

“When I was growing up, there was Jim Brown, Jim Brown and Jim Brown,” said Foreman, now 72. “He was bigger than most linemen and faster than most wide receivers. But he also left on his own terms, especially back in those days, being an outspoken Black man.”

Foreman, like many others, called him Mr. Brown. But as they talked, the younger running back’s fears dissolved. Brown complimented Foreman’s style of play and his success with the Vikings. Then he gave Foreman some advice that has stuck ever since.

“‘Know when to go down,’” Foreman said Brown told him. “‘Don’t jeopardize your career over two inches.’”

Brown, Foreman said, wasn’t just telling him to run smart, he was telling him to think about his future and not sacrifice his body needlessly.

Though he didn’t say it, Brown, who died on Friday at 87, could have also been talking about life outside of football. In a game with a 100 percent injury rate, few N.F.L. players leave because they want to. Most wind up with injuries that never heal and are ushered out of the game once their utility to coaches is gone. Those who retire when they want to often do so because teams are not interested anymore.

Brown was the opposite. He left the N.F.L. after the 1965 season, his ninth in the league and one of his best. He ran for 1,544 yards and 17 rushing touchdowns, and caught 34 passes, four of them for scores. He was voted the league’s Most Valuable Player for the first time since his second season.

His rushing records — most notably his 12,312 yards on the ground — were eventually broken by Payton, Barry Sanders, Emmitt Smith and others. But Brown’s career lasted just nine years and he played mostly 14-game seasons, rather than 16- or 17-game campaigns, at a time when chop blocks and other dangerous tackles were allowed. His 104.3 rushing yards per game average still stands as a league record.

Then he walked away, opting to pursue a Hollywood career making movies and more money than in Cleveland. His breaking point came when he was filming “The Dirty Dozen.” Brown told Art Modell, the team’s owner, that he would be late to training camp. Modell said he would fine Brown for every day he missed camp. Offended, Brown called a news conference to announce that he was leaving the N.F.L.

By that point, Brown had accomplished more in football than many do in much longer careers, including winning a league title in 1964, three M.V.P. awards, and owning the N.F.L.’s career rushing record. But only a handful went out on top. John Elway and Peyton Manning won Super Bowls in their last seasons, but both were no longer in their prime. Sanders retired from the Detroit Lions when he was just 30, but won just one playoff game.

Brown, on the other hand, was a kind of Mount Rushmore figure, a running back of stature who helped redefine the power an athlete could have on and off the field by demanding that owners and coaches treat players — particularly Black players — with respect.

“You can make a case that Wilt Chamberlain was his own man in basketball, but Jim Brown would have been the first pro football player in the modern era to have that kind of presence and sway,” said Michael MacCambridge, the author of “America’s Game: The Epic Story of How Pro Football Captured a Nation.” “It was clear that Jim Brown was a different generation of player with a different mind-set.”

Players who came after him knew about that difference.

“There isn’t a man who played running back in the NFL who didn’t see Jim Brown as an iconic legend on and off the field,” Tony Dorsett, one of 10 running backs to surpass Brown’s total rushing yards, wrote on Twitter.

“You can’t underestimate the impact #JimBrown had on the @NFL,” Sanders also wrote on Twitter.

As exceptional as he was on the field, Brown was far from a perfect human being. He was arrested more than a half-dozen times, including for multiple accusations of violence against women. He was never convicted of a major crime.

But when it came to the sport that made him famous, Brown had few equals. Ernie Accorsi, the Browns general manager from 1985 to 1992, was in high school when he saw Brown play in person against the Baltimore Colts in 1959. Brown ran for five touchdowns and 178 yards to beat the defending champions and, to Accorsi, it felt like watching Babe Ruth in his prime.

Years later, Accorsi worked in the Colts’ front office alongside Dick Szymanski, who had been Baltimore’s middle linebacker in that game in 1959. Szymanski told Accorsi that Weeb Ewbank, the Colts’ head coach at the time, had advised that Brown was tipping his plays: When Brown lined up with his right hand in the dirt, he was running right, and vice versa.

Brown still ran all over Szymanski, and in the locker room after the game, Ewbank told Szymanski that he hated to think what Brown’s rushing totals would have been if he hadn’t given Szymanski the tips.

“Coach, I knew exactly where he was going, but I couldn’t catch him or tackle him,” Szymanski replied.

In Brown’s illustrious career, few could.