The athlete-turned-actor succumbed to kidney failure on Wednesday (October 10), a family spokesperson has confirmed.
Karras was reported earlier this week to be living in a hospice centre in California for kidney problems as well as dementia.
He rose to fame in the 1950s as a defensive tackle for the Detroit Lions, with whom he played on and off from 1958 to 1970. He recently joined a lawsuit against the NFL, blaming his dementia on his years in the league.
The football player also worked as a professional wrestler during a suspension from the NFL in the 1960s.
Karras later transitioned into acting with a starring role as Mongo in director Mel Brooks's comedy classic Blazing Saddles in 1974.
He also appeared with wife Susan Clark and Emmanuel Lewis in the 1980s sitcom Webster, which aired for six seasons.
The star is survived by wife Clark and their daughter as well as five children from a prior marriage.
Watch Alex Karras in a clip from Blazing Saddles:
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