Jeffrey Kessler just had to pee.

It was the fall of 1975, and the Columbia law student was interviewing for an internship at Weil, Gotshal & Manges, a prominent New York firm known for its prowess in antitrust litigation, the area of law hed decided was his future.

As he walked into the mens room after his interview, he noticed a group of extremely tall men shuffle in behind him. One of them stepped up to the urinal next to him. It was Kareem Abdul-Jabbar, the 7-foot-tall Los Angeles Lakers superstar. Kessler was stunned, even a little confused.

Antitrust law and the world of professional sports had begun to overlap in the decade prior, when St. Louis Cardinals outfielder Curt Flood sued Major League Baseball to overturn the leagues reserve clause, which bound players to their teams and restricted their salaries unless they were traded. But until the moment Abdul-Jabbar sidled up next to him at the urinal, Kessler hadnt realized that his firm was at the center of another major sports case: a lawsuit brought by Milwaukee Bucks guard Oscar Robertson, the head of the NBAs players union, that aimed to end the NBAs version of the reserve clause, which limited free agency rights and gave teams near-complete control over their players.

Kessler was a sports fan, and had long harbored an urge to work in public service. Growing up in the Sea Gate neighborhood in the outer reaches of Brooklyn, he was hardly a hippie, but he found it impossible to ignore the civil rights, feminist and anti-war movements erupting around him. An accomplished student, Kessler felt called to use his abilities to do some good in the world, and he saw the law and antitrust law, specifically as a way to do that. But at a time when the U.S. government had found a renewed zeal for using antitrust law to take on giant corporate monopolies, hed never considered a future in sports law. Now he was surrounded by NBA players whod come to Manhattan to take part in Robertsons case.

I remember going home to my wife and saying, Youre not going to believe who I saw in the mens room today, Kessler said.

Kessler never actually worked on that Robertson case. But soon after it settled, he joined the firm full-time, and over the next four decades, he would establish a reputation as one of the nations pre-eminent sports lawyers a bulldog attorney willing to take up the cause of virtually any athlete who felt he (or she) had been wronged by the league above them. He began representing NBA players in the 1970s and NFL players in the 80s. He represented Freeman McNeil, the running back who sued the NFL in 1990, and won the 1992 decision that established free agency rights for professional football players. Hes worked on behalf of all four major mens professional sports unions and the United States womens national soccer team. He has counted Michael Jordan, Patrick Ewing, Tom Brady and Bill Belichick among his clients.

All of that has led to perhaps the biggest case of his career: Jenkins v. the NCAA. The case, which Kessler filed on behalf of three college athletes in 2014 , could upend major college sports as we know them.

Although there have been other major lawsuits against the NCAA in recent years, none have targeted the entire system of college athletics quite like this one. Kessler and his plaintiffs arent seeking monetary damages. Instead, they want federal courts to rule that the existing model of major college sports specifically, mens basketball and football violates federal antitrust law. If they win, they could reshape the current collegiate sports structure, forcing schools and major conferences to finally pay athletes in their two biggest sports.

But the case, like many of his previous battles in sports, isnt just about money: To Kessler, its fundamentally a fight for college athletes rights.

If we win, Kessler told HuffPost, it could make a big difference.