WASHINGTON — Buddy Ryan, whose innovative defensive scheme propelled the 1985 Chicago Bears to one of the most dominant seasons in NFL history, one that culminated in a crushing Super Bowl victory over the New England Patriots, died Tuesday at the age of 85. Mr. Ryan had been in poor health, learning he had salivary gland cancer in 2011.

Mr. Ryan spent much of his long NFL career as an assistant coach before finally ascending to a top job in 1986 with the Philadelphia Eagles. He coached Philadelphia to three playoff appearances but never won a postseason game. He was head coach of the Arizona Cardinals for two seasons in 1994 and 1995, compiling a 12-20 record there and a 55-55-1 overall record as a head coach.

His twin sons, Rex and Rob, also became NFL coaches — Rex Ryan is the head coach of the Buffalo Bills and Rob one of his top assistants.

Beloved by his defensive players, Mr. Ryan openly warred with Bears coach Mike Ditka during the memorable 1985 season, in which the Bears went 15-1. Mr. Ryan refused to let Ditka have any say in how his innovative ‘‘46’’ scheme was run, at one point nearly coming to blows with Ditka at halftime of a game.

After he was fired by the Eagles in 1991, Mr. Ryan became defensive coordinator of the Houston Oilers in 1993, memorably getting into a sideline fight with offensive coordinator Kevin Gilbride in the regular season finale in 1993.

For all his football intellect, Mr. Ryan embraced pure aggression.

“It got mean, cruel,’’ defensive end Gerry Philbin, who played under Mr. Ryan at the University of Buffalo and on the New York Jets, once told Sports Illustrated. “I’ve never seen anyone better at bringing the animal out of you. If you didn’t hit as hard as he wanted, he’d humiliate you in front of everyone. Guys like me loved him, though. He was just so brutally honest.’’

When Mr. Ryan became the Eagles’ head coach and subjected his players to punishing drills in training camp, he spoke of his mindset.

“They probably think I’m a no-good so-and-so,’’ he told The New York Times. “But that’s all right. That breeds closeness as a team. That way they can all dislike the same guy.’’

His son Rex, having earned a reputation for brashness in his own right while coaching the Jets, wrote in a memoir that he grew up “wanting to be Buddy Ryan,’’ though he acknowledged his father “was a little over the top from time to time.’’

Mr. Ryan wasn’t without detractors who said he coached dirty, a charge backed up by the comments of his former players in a Sports Illustrated story from July 1994.

‘‘Told us that if a quarterback scrambles, you go for his knees,’’ former Bears defensive back Dave Duerson said.

‘‘Told us that when one of us made an interception, the other 10 guys were to go block the quarterback,’’ former Bears defensive back Doug Plank said. ‘‘It was comical on film! You’d see the quarterback get hit, go down, get up, get hit, go down, get up, get hit…’’

‘‘Buddy Ryan is a Neanderthal, and he attracts Neanderthal players,’’ said Bill Parcells, former head coach of the New York Giants, New England Patriots, New York Jets, and Dallas Cowboys.

Nevertheless, the 1985 Bears will go down as perhaps the most fearsome defense in NFL history, allowing just 12.4 points per game and posting four shutouts. During one seven-game stretch, Chicago never allowed its opponent to score more than 10 points and won by an average score of 27-6.

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

‘‘That’s something my dad was very proud of,’’ Rex said. ‘‘When (former Jets coach Weeb) Ewbank hired him, he had to make a difference. If he felt he wasn’t making a difference, then his career as a professional coach would be short.’’

Instead, it was very long.

Mr. Ryan’s first job as a defensive coordinator came in 1976 with the Vikings under Bud Grant, like Ewbank a Hall of Fame coach. 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.

Ryan’s defenders, featuring such Hall of Famers as linebacker Mike Singletary and ends Dan Hampton and Richard Dent, came from all angles and were nearly impossible to budge on the ground. Teams had little success in the air, as well.

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

His work in Chicago got Mr. Ryan the Eagles job.

At a meeting the night before the Bears beat New England in the 1986 Super Bowl, Dent said a teary Mr. Ryan informed his players that he was going to Philadelphia:

‘‘You guys are going to be my champions. Let’s kick some tail,’’ Mr. Ryan said.

Hampton then kicked a film projector out of defensive line coach Dale Haupt’s hands, and defensive tackle Steve McMichael flung a chair across the room, its legs impaling a chalkboard.

Such was the devotion players felt for Mr. Ryan.

In addition to Rex and Rob, Mr. Ryan leaves another son, Jim, the Eagles said.

Material from the Washington Post, Associated Press, and New York Times was used in this obituary.