Freddie Kitchens will serve as the team's offensive coordinator, following the firing of Todd Haley. The Browns announced the moves on Monday.
Williams, 60, has a 17-31 record in three seasons as a head coach. He held that role from 2001 through 2003, before his contract wasn't renewed by the Buffalo Bills. He entered the NFL ranks in defensive quality control in 1990 with the Houston Oilers. Williams also worked with the Tennessee Titans, Washington Redskins, New Orleans Saints, St. Louis Rams and Los Angeles Rams before landing in Cleveland in 2017.
The Browns ranked 31st in points allowed and last in takeaways last season, en route to an 0-16 campaign.
"We greatly appreciate Hue's commitment to the Cleveland Browns organization over the last two and a half years," Browns owners Dee and Jimmy Haslam said in a statement regarding Jackson. "We understand how critical this time period is in the development of our football team, individually and collectively, and believed it was in the organization's best interest to make the move at this time, in order to maximize our opportunities the rest of this season. We certainly only wish Hue, Michelle, and his family the best moving forward."
The Browns host the Kansas City Chiefs at 1 p.m. on Sunday in Cleveland.