Williams, an offensive tackle from Vanderbilt, was the No. 14 choice overall. The Bears announced the deal two hours before their first practice. Financial details were not disclosed.
The 6-foot-6, 312-pound Williams is expected to be the Bears' left tackle with John Tait moving from the left side to the right.
Williams appeared in 36 games at left tackle and left guard while at Vanderbilt, finishing his college career with 33 consecutive starts. He was chosen first team all-Southeastern Conference as a senior.