The cause was respiratory complications related to a long illness, said his friend and law partner of nearly 35 years, Joe Rice.

The son of a gas station owner and a schoolteacher, Mr. Motley rose to the heights of the legal profession, displaying a startling memory for detail and an ability to get his ideas across, connecting evidence and courtroom tactics seemingly on the fly. William S. Ohlemeyer, a lawyer who opposed him in a 1998 case in Indiana involving environmental tobacco smoke, said, "When you were in court and he was sitting behind you, you could almost feel him thinking."

Mike Moore, the former Mississippi attorney general who hired Mr. Motley along with a local lawyer, Richard Scruggs, to help spearhead state efforts to sue tobacco companies over the health consequences of smoking in the early 1990s, said the choice to bring in Mr. Motley and Mr. Rice was easy: "We needed tough litigators who could help not only fund the case, but pick on some of the big national law firms we were going to fight."

Mr. Motley and Mr. Moore flew around the country recruiting other states; eventually 46 would take part in the effort. The legal pressure led to a staggering $246 billion settlement with the industry in 1998.

Mr. Motley's advocacy in those cases earned him a moment of fame in Hollywood's version of the tobacco wars: the movie "The Insider," about the whistle-blower Jeffrey S. Wigand. Mr. Motley was played by Bruce McGill, and his bellowed "Wipe that smirk off your face!" to a tobacco industry lawyer stands out as a moment of high drama in the film. (Russell Crowe played Mr. Wigand.)

The fees for the law firms in the tobacco cases alone amounted to billions of dollars. And while those fees were distributed among the many firms that participated, Mr. Motley became wealthier than many of the executives he sued. The Post and Courier of Charleston noted that he owned a private plane, a mansion on nearby Kiawah Island and a 156-foot yacht, Themis, named after the female Greek titan of law.

Even those skeptical of the mass tort system, in which lawyers gather clients from all over the country to sign on to class-action suits, recognized his skills. Victor Schwartz, a general counsel to the American Tort Reform Association, called Mr. Motley "a visionary" who had "gambled with the law more than most plaintiff's lawyers."

"But his game of chance often meant success for both him and his clients," Mr. Schwartz said.

Mr. Motley was not above pulling a stunt to get a point across. Mr. Rice recalled a major asbestos case in Baltimore in which a witness for the companies involved, a doctor, gave some six hours of expert testimony asserting that the plaintiffs had not actually been ill. Mr. Motley followed up by coming into the courtroom wearing a doctor's lab coat, and through pointed questioning emphasized that the doctor on the stand had been paid for his testimony and had never met the patients he was speaking about.

"He was conveying to the jury that just because you wear a piece of clothing, it doesn't make you an expert," Mr. Rice recalled. "Ron flipped that whole jury away from that five- or six-hour testimony in five minutes."

The asbestos company lost, and the white coat was part of its argument to have the verdict overturned. But the appeals courts let it stand. That and other lawsuits led to bankruptcy filings by many of the companies in the asbestos industry.

In 2002, Mr. Motley and Mr. Rice formed a new law firm that would take their practice in a new direction.

"We made some money in tobacco — we made a living," Mr. Rice recalled. "We decided we'd make a difference. We decided on taking on causes, not cases."

The new firm filed lawsuits on behalf of 6,500 family members and survivors of the 9/11 attacks against those who the lawyers say were the terrorists' financiers. The cases, under the umbrella organization 9/11 Families United to Bankrupt Terrorism, are working their way through the courts.

Linda Lipsen, the chief executive of the American Association for Justice, recalled Mr. Motley as "a fearless advocate who took the impossible cases no one else would take." The organization awarded Mr. Motley its highest honor, the lifetime achievement award, in 2010.

Mr. Motley was born on Oct. 21, 1944. He grew up in North Charleston and received a bachelor of arts degree and a law degree from the University of South Carolina. He was married five times, Mr. Rice said. Mr. Motley's son, Mark, died in 2000 after an error in medical treatment.

Mr. Motley is survived by his wife, Stephanie; a daughter, Jennifer Lee; and three grandchildren.

"Ron worked hard, and he partied hard," recalled Mr. Moore, the former Mississippi attorney general. He once got to see, close up, his star litigator's renowned capacity for carousing on a trip to St. Louis to meet with attorneys general at a conference.

Mr. Motley, he recalled, went out one evening with friends and was not back at the hotel until well after 1 a.m. "He'd told me he wanted to go running the next morning," Mr. Moore said, but he figured that those plans would give way to Mr. Motley's need to rest and recover.

"The next morning at 5:30, my phone rings." Mr. Moore said. "It's Ron. 'You ready to run?' " He was downstairs.

After a six-mile run, Mr. Moore said, Mr. Motley worked until 10 that night.