The News Star in Monroe, La. reports that Williams, who was in his second stint as the head football coach at the Louisiana school, was fired personally and suddenly by university President Frank Pogue.
"There wasn't a lot of conversation," Williams told the News Star. "I told him 'OK' and I was gone."
Williams is most known in Washington as being the first African-American quarterback to lead his team to a Super Bowl title. His Redskins captured Super Bowl XXII in 1987, earning the game's MVP honors in a blowout of the Denver Broncos.
He played his college football at Grambling under legendary head coach Eddie Robinson in the 1970s, earning All-American honors during his 1977 senior season.
After his NFL career ended, Williams returned to Grambling for two separate stints as the school's head football coach. The 2012 season was a struggle, though, with the team going 1-10.