"Perhaps no player in Lions history attained as much success and notoriety for what he did after his playing days as did Alex," Lions president Tom Lewand said.
His death also will be tied to the NFL's conflict with former players over concussions. Mr. Karras in April joined the more than 3,500 football veterans suing the league for not protecting them better from head injuries, immediately becoming one of the best-known names in the legal fight. Mitnick said the family had not yet decided whether to donate Karras' brain for study, as other families have done.
Born in Gary, Ind., Mr. Karras starred for four years at Iowa. Detroit drafted Mr. Karras with the 10th overall pick in 1958, and he was a three-time all-pro defensive tackle over 12 seasons with the franchise.
He was the heart of the Lions' famed "Fearsome Foursome," terrorizing quarterbacks for years. The Lions handed the powerful 1962 Green Bay Packers their only defeat that season, a 26-14 upset on Thanksgiving during which they harassed quarterback Bart Starr constantly.
Packers guard Jerry Kramer wrote in his diary of the 1967 season about his trepidation over having to play Mr. Karras.
"I'm thinking about him every minute," Kramer wrote.
For all his prowess on the field, Mr. Karras may have gained more fame when he turned to acting in the movies and on television.
Playing a not-so-bright bruiser in Mel Brooks' Blazing Saddles, he not only slugged a horse but also delivered the classic line: "Mongo only pawn in game of life."
Several years before that, Mr. Karras had already become a bit of a celebrity through George Plimpton's behind-the-scenes book about what it was like to be an NFL player in the Motor City, Paper Lion: Confessions of a Second-String Quarterback.
That led to Mr. Karras' playing himself alongside Alan Alda in the successful movie adaption. It opened doors for Mr. Karras to be an analyst alongside Howard Cosell and Frank Gifford on Monday Night Football.
In the 1980s, he starred as Emmanuel Lewis' adoptive father, George Papadapolis, in the sitcom Webster. He portrayed George Zaharias in CBS's Babe, in which he starred with Susan Clark, who later became his wife.
His wife said Mr. Karras' quality of life had deteriorated because of head injuries suffered during his playing career.
"This physical beating that he took as a football player has impacted his life, and therefore it has impacted his family life," Clark told the Associated Press earlier this year. "He is interested in making the game of football safer and hoping that other families of retired players will have a healthier and happier retirement."
Mr. Karras played his entire NFL career with the Lions before retiring in 1970 at age 35. He was a first-team all-pro in 1960, 1961, and 1965, and he made the Pro Bowl four times. He missed the 1963 season when he was suspended by NFL commissioner Pete Rozelle in a gambling probe. Mr. Karras was recognized by the Pro Football Hall of Fame as a defensive tackle on the all-decade team of the 1960s.