Briggs played alongside Pro Football Hall of Fame linebacker Brian Urlacher during his tenure with the Bears.

[7] Head coach Dick Jauron named Briggs a backup outside linebacker to start his rookie season, behind Bryan Knight and Warrick Holdman.

On October 5, 2003, Briggs earned his first career start and recorded one solo tackle during a 24–21 win against the Oakland Raiders in Week 4.

Briggs made his first career interception off a pass by Packers' quarterback Brett Favre and returned it for a 45-yard touchdown during the first quarter.

[9] He finished his rookie season in 2003 with 78 combined tackles (65 solo), four passes defended, one interception, and one touchdown in 16 games and 13 starts.

After the two sides reached an impasse, Briggs refused to attend the team's voluntary workouts and missed part of training camp.

[11] During the season, Briggs was a major contributor to the Bears' defense that reached Super Bowl XLI.

[14] Briggs was dissatisfied with the move, commenting, "I am now prepared to sit out the year if the Bears don't trade me or release me, I've played my last snap for them.

[17][18] Despite his comments, Briggs played for the Bears during the 2007 season, where he accrued 140 total tackles and earned his third Pro Bowl selection.

[20] On September 2, 2011, Briggs and his agent, Drew Rosenhaus, formally asked the Bears organization for a trade, with three years left on his six-year contract.

In 2020, alongside Kyle Higgins and Danilo Beyruth, he co-created The Trap, a science fiction original graphic novel, on Kickstarter, which was set to be published in 2021.