He played in the National Football League (NFL) for the Dallas Cowboys, Miami Dolphins, and Seattle Seahawks.

On November 27, 2017, Williams announced that he would forgo his senior year in favor of the 2018 NFL draft, and that he would not play in the 2017 Texas Bowl.

[3] Williams was selected by the Dallas Cowboys in the second round (50th overall) of the 2018 NFL draft, with the intention of playing him at guard.

He started 11 games, missing one due to arthroscopic knee surgery, before suffering a torn right ACL in Week 13.

[9] In 2020, he was able to recover from a torn ACL to start all 16 games at left guard for the first time in his career, missing just one snap on offense (in the season opener).

He got his starting position back in Week 15, but struggled in the final five games of the season, ranking second in the league with 15 penalties (13 for holding).

He still managed to finish the year with the fewest pressures allowed by any Cowboy offensive lineman to start a game and surrendered only one sack.

[13][14] During training camp, he confirmed he was "focused on football, straight on," while the Dolphins waited to make cap space.

[16] On August 29, Dan Feeney was traded to the Chicago Bears, leaving Williams as the first-string center.

He suffered a season-ending left ACL tear in Week 14 against the Tennessee Titans and was placed on injured reserve on December 13, 2023.

[21] During the offseason there were concerns about his chances to rebound from the injury, which caused the Dolphins to move on from him and sign Aaron Brewer instead.