The 22-year-old, widely regarded as one of the most talented players to come out of college for years, was one of a record six quarterbacks taken in the first 12 picks.
No defensive players were taken in the top 10 for the first time in NFL Draft history, as the night started with 14 straight offensive players being chosen.
A record 250,000 fans packed out downtown Detroit for the first round of the draft, which continues with six further rounds of selection across Friday and Saturday
For just the fourth time, the first three picks off the board were quarterbacks as Jayden Daniels followed Williams when picked by the Washington Commanders and Drake Maye was chosen by the New England Patriots.
While those picks were expected, the Atlanta Falcons then shocked the crowd by also picking a quarterback, Washington’s Michael Penix Jr, despite signing Kirk Cousins in the off-season in a deal which guarantees the veteran $100m.
The Minnesota Vikings traded up a spot to select JJ McCarthy, who won the college National Championship with Michigan, as their new quarterback with the 10th pick.
There was still time for a sixth quarterback to come off the board though as Oregon’s Bo Nix was taken with the 12th pick by the Denver Broncos.
Three wide receivers, four offensive linemen and a tight end all got the call in the first 14 picks before Laiatu Latu became the first defensive player to be picked when the Indianapolis Colts drafted him.
Bears pin revival hopes on Williams
It is Williams who made the headlines as the first overall pick after a stellar career first at Oklahoma and later with the University of Southern California (USC).
He won the 2022 Heisman Trophy as the best college player that year, but now faces a bigger challenge in trying to revive the fortunes of one of the oldest and most storied teams in the NFL which has been underachieving for years.
Williams passed for 93 touchdowns and ran in 27 more in his 33 college starts, but now has to turn around a team without a play-off win since 2010.
Chicago have helped him out somewhat as they also used their ninth pick of the draft to select talented Washington wide receiver Rome Odunze as an elite young target – after also adding veteran Keenan Allen earlier in the off-season.
“It’s an honour and a privilege,” a tearful Williams told the NFL Network after being drafted.
“I care about the fans, the community, the players and the coaches and I care about the Chicago Bears.”
Williams and Odunze were on the same flight to Detroit for the draft, and will now be team-mates in the most exciting looking attack in Chicago for years, and the receiver thinks they “can do amazing things”.
“It’s going to take a lot of work, a lot of determination,” Odunze added to NFL Network. “I can tell he has the same determination as I do. He is special.”
The Vikings added to their quarterback pick with another trade to get edge rusher Dallas Turner, while the Los Angeles Rams spent their first pick in the first round since 2017 on another edge rusher in Jared Verse.
Super Bowl champions the Kansas City Chiefs made an eye-catching selection as they traded up to get speedy wide receiver Xavier Worthy.
The Texas Longhorns wideout hit the headlines at the NFL Combine by clocking a record time in the 40-yard dash, so will offer Patrick Mahomes another attacking weapon as the Chiefs look to win three titles in a row.