Buddy Ryan took a back seat to no one. Neither did his fierce defenses that won two Super Bowls.

The pugnacious coach and defensive mastermind, whose twin sons have been successful NFL coaches, died Tuesday. He was 82.

His death was confirmed by the Buffalo Bills, where Rex Ryan is the head coach and Rob Ryan an assistant. James Solano, Buddy Ryan’s agent, said he died in Kentucky but did not give a cause. Mr. Ryan lived on a ranch in Shelbyville.

“His knowledge, passion for football and the love he had for his players and coaches are traits that have shaped and influenced so many careers, including my own,” said Rams coach Jeff Fisher, who played for and got his coaching start under Mr. Ryan.

Mr. Ryan was a linebackers coach for the 1968 champion New York Jets and coordinated the ground-breaking 46 defense for the title-winning 1985 Chicago Bears, one of the NFL’s greatest defenses. He was a head coach for the Philadelphia Eagles from 1986-90 and for the Arizona Cardinals in 1994-95, compiling a 55-55-1 overall record.

A few years ago, Mr. Ryan attended a Cowboys-Jets game, traveling to New Jersey despite cancer to see then-Jets head coach Rex go against then-Dallas defensive coordinator Rob.

“Buddy Ryan was the architect of the greatest defense our league has seen,” said Bears chairman George H. McCaskey. “He was brilliant when it came to the Xs and Os of the game, but what made him special was his ability to create an unwavering confidence in the players he coached. From the day he was hired in 1978, his defenses bought into more than the scheme, they bought into him and took on his personality. Buddy was brash, intelligent and tough.”

James David Ryan was a Korean War veteran who went to Oklahoma State, then earned a master’s degree from Middle Tennessee State even while coaching. He got his first major job in the pros in New York, then of the AFL, in 1968. Mr. Ryan was the linebackers coach for the Joe Namath-led Jets, a boastful, confident team that fit his personality.

Those Jets led the AFL in defense in his first season on staff, then shocked the Colts in the Super Bowl, 16-7.

Mr. Ryan’s first job as a defensive coordinator came in 1976 with the Vikings under Bud Grant. He spent two years there, with the 1976 team losing to Oakland in the Super Bowl. He then moved to the rival Bears, where he concocted the 46 defense that overwhelmed the league with its aggressiveness and unpredictability.

Mr. Ryan’s defense, featuring such Hall of Famers as linebacker Mike Singletary and ends Dan Hampton and Richard Dent, came from all angles and was nearly impossible to budge on the ground. Not that teams had more success in the air, either.

“Some say the 46 is just an eight-man front,” said Mr. Ryan, who named the scheme after safety Doug Plank, who wore that number. “That’s like saying Marilyn Monroe is just a girl.”