Bielema served as the head football coach at the University of Wisconsin–Madison from 2006 to 2012, achieving a 68–24 record and taking them to three straight Rose Bowl Games, although they lost each time.

Bielema was an assistant coach in the National Football League (NFL) for three seasons, in 2018 and 2019 with the New England Patriots and in 2020 with the New York Giants.

After going undrafted in the 1993 NFL draft, Bielema signed as a free agent with the Seattle Seahawks, but was cut during the summer.

[11] During his three years with Ferentz at Iowa, Bielema recruited several players, most from Florida, that would form part of the core of the 2002 Iowa team, including Heisman runner-up quarterback Brad Banks, wide receivers C. J. Jones and Maurice Brown, nose tackle Colin Cole, cornerback Antwan Allen, and linebackers Fred Barr and Abdul Hodge.

Bielema and Bob Elliott replaced Phil Bennett, who had left to become the head coach of the SMU Mustangs.

Bielema coached the K-State defense for two seasons, helping the Wildcats win the 2003 Big XII Championship.

[18] With a 14–0 victory over San Diego State on September 16, 2006, Bielema became the third Wisconsin head coach to win the first three games of his career.

[20] A 30–24 victory over the Fighting Illini on October 28, Bielema became the first coach in Wisconsin history to win eight games in his first season.

[21] With the 35–3 defeat of the University at Buffalo on November 18, 2006, Bielema became the first coach in school history to win 11 games in the regular season.

[22] After a 17–14 victory over the Arkansas Razorbacks in the Capital One Bowl on January 1, 2007, he became the third coach in NCAA history to win 12 games in his rookie season, finishing 12–1.

The other finalists were Chris Ault of Nevada, Gene Chizik of Auburn, Mark Dantonio of Michigan State, Jim Harbaugh of Stanford, Chip Kelly of Oregon, Gary Patterson of TCU, Bobby Petrino of Arkansas, and Mike Sherman of Texas A&M.

[43] Bielema replaced John L. Smith, who had coached Arkansas to a 4–8 record during the 2012 season after Bobby Petrino had been fired eight months earlier.

[48][49] Though Arkansas lost its remaining conference game against Missouri, the Razorbacks were still the first unranked team in college football history to shut out two consecutive ranked opponents.

[55] Bielema ended the year by defeating one of his former mentors, Bill Snyder, in the AutoZone Liberty Bowl, as Arkansas dispatched Kansas State, 45–23, to finish the season with a record of 8–5.

[59] Beating Missouri would have resulted in Bret Bielema improving his regular season record every year at Arkansas.

[62] On November 24, 2017, Bielema was fired after five seasons as Arkansas's head coach following a 48–45 loss at home to the Missouri Tigers.

[64] According to Fox Sports' Bruce Feldman, school officials decided to announce the firing after the game so he could have a chance to address the team one last time before they headed home for Thanksgiving.

[65] Prior to the 2018 NFL season, Bielema was hired by the New England Patriots as a defensive consultant to head coach Bill Belichick.

[71] The salary makes him the ninth-highest paid head coach among the fourteen members of the Big Ten Conference.

Bielema won his first game with the Illini against the Nebraska Cornhuskers then went on a four-game losing streak to UTSA, Virginia, Maryland and Purdue.

Following an off week, Bielema and the Fighting Illini upset 24.5-point favorite Penn State in Happy Valley, then ranked #7 in the AP Poll.

Mississippi State, inspired by the untimely death of their head coach Mike Leach, beat Illinois 19–10 in the bowl.

1 Oregon in a blowout victory for the Ducks, and lost at home to the Minnesota Golden Gophers in a close game where quarterback Luke Altmyer fumbled the ball on a potential game-tying drive.

The Illini then won three straight games, including a win at Rutgers, where wide receiver Pat Bryant scored a 40 yard touchdown on a pass from Luke Altmyer with 14 seconds left to seal the victory.

The three game win streak to end the regular season was capped off by reclaiming the Land of Lincoln Trophy against the Northwestern Wildcats.

15 South Carolina Gamecocks, where they emerged victorious riding a 2 touchdown performance from running back Josh McCray.