"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. 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., Karras starred for 4 years at Iowa. Detroit drafted Karras with the 10th overall pick in 1958, and he was a four-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 Karras.
"I'm thinking about him every minute," Kramer wrote.
For all his prowess on the field, Karras may have gained more fame when he turned to acting in the movies and on television.
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, 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 Karras playing himself alongside Alan Alda in the successful movie adaption, and it opened doors for Karras to be an analyst alongside Howard Cosell and Frank Gifford on "Monday Night Football."
In the 1980s, he played a sheriff in the comedy "Porky's" and became a hit on the small screen as Emmanuel Lewis' adoptive father, George Papadapolis, in the sitcom "Webster."
He also had roles in "Against All Odds" and "Victor/Victoria." He portrayed the husband of famed female athlete "Babe" Didrikson Zaharias in the TV movie that starred Susan Clark, who later became his wife. The two formed their own production company and it was Clark who played the role of his wife on "Webster."
Recently, his wife said Karras' quality of life has deteriorated because of head injuries incurred during his playing career. Clark has said he was formally diagnosed with dementia several years ago and has had symptoms for more than a dozen years.