Illinois coach Tim Beckman said in a news release Monday that he hopes Williams helps move the program forward. He also noted that the Chicago native still has strong connections in his home city.
Williams said he looks forward to helping Illinois with recruiting and building ties with former players.
Williams is second in career total yardage at Illinois with 10,594 yards. He helped lead the team to the 2008 Rose Bowl.
He takes on part of the role that Matt Sinclair filled until he resigned in February. Sinclair left after pleading not guilty to charges he pointed an unloaded handgun at a vehicle containing other Illini staff members.