He has served as the head coach of the Chicago Bears, Tampa Bay Buccaneers, and Houston Texans of the National Football League (NFL) and the Illinois Fighting Illini.

[1] During Smith's high school career at Big Sandy, he earned all-state honors for his three years as a defensive end and linebacker.

In 1975, Big Sandy had one of the most dominant seasons in high school football history, as the defense allowed only 15 points (11 shutouts) all season; Their offense, featuring eventual Miami Dolphins running back David Overstreet, scored a then-national record 824 points.

A year later, he left for Cascia Hall Preparatory School in Tulsa, where he coached defensive backs and wide receivers from 1981 to 1982.

After spending five years with the Buccaneers, Smith was hired as the defensive coordinator of the St. Louis Rams under head coach Mike Martz.

The team ultimately lost to the New England Patriots in one of the biggest Super Bowl upsets of all time.

After returning to the field following their first round bye, the Bears played the Carolina Panthers, with a fully-healed Grossman at quarterback.

[9] Smith and the Bears' management drew criticism in April 2006 by trading away their first round pick, as well as drafting five defensive players.

Hours later, the Indianapolis Colts' head coach, Tony Dungy, Smith's good friend and mentor, became the second.

[18] In 2007, Smith, confident in Rex Grossman's abilities, named him the team's starting quarterback over Kyle Orton and Brian Griese.

Griese led the Bears to a 2–3 record,[19] but sustained an injury against the Oakland Raiders, which allowed Grossman to become the team's starting quarterback again.

Smith ultimately allowed Orton to finish the remainder of the season, who led the Bears to a 2–1 record.

The next year, Smith and the Bears parted ways with their leading rusher Cedric Benson, as well as passer Griese, and receiver Bernard Berrian.

Smith was pleased with the success of Orton, who finished the season with a 79.6 quarterback rating, as well as rookie running back Matt Forte.

He was also reunited with long-time friend, Rod Marinelli, who had lost his head coaching job with the Detroit Lions.

[21] In the 2009 offseason, Smith and the Bears' general manager Jerry Angelo had conflicting views on the future of the team's quarterback position.

The Bears were eliminated from the playoff race for the third consecutive year, after losing to the Green Bay Packers during a Week 14 matchup.

The loss marked the first time that the Bears, under Lovie Smith, had ever lost two games to Green Bay in a single season.

[35] Prior to sitting out the 2013 season, Smith interviewed with the Philadelphia Eagles[36] and the Buffalo Bills,[37] regarding their head coaching vacancies.

"[38][39] Smith also interviewed for the head coaching vacancies held by the Houston Texans[40] and the Detroit Lions,[41] prior to securing the role with the Buccaneers.

[42][43] On March 7, 2016, Smith returned to college football and was named head coach for the University of Illinois, agreeing to a contract paying $21 million over six years.

[49] In Smith's first season leading the Texans' defense in 2021, Houston recorded 25 total takeaways, which tied for 10th in the NFL, while intercepting 3.1% of opponent passing attempts, the fifth-highest rate in the league.

[53] The firing occurred hours after the Texans won their season finale against the Indianapolis Colts, which cost them the first overall pick in the 2023 NFL draft.

[55][58] He was the Grand Marshal for the USG Sheetrock 400 NASCAR Nextel Cup Series race at Chicagoland Speedway on July 15, 2007.