He played college football for the Michigan Wolverines, twice earning first-team All-American honors, and was selected by the Titans in the first round of the 2014 NFL draft.

[4] Sources: Lewan enrolled at the University of Michigan in 2009, where he majored in general studies, and redshirted his freshman year.

[7] In 2010, Lewan took over the starting left tackle role from Mark Huyge in the fourth game versus Bowling Green.

[12] Lewan was Michigan's starting left tackle in the first seven games of the season and was named to Phil Steele's Midseason All-Big Ten second team.

[31] In his rookie year in 2014, Lewan played in 11 games and started in six of them due to injuries, he was named to the PFWA All-Rookie team.

On October 23, 2016, Lewan scored his first NFL touchdown on a 10-yard pass from Marcus Mariota in a 34–26 loss to the Indianapolis Colts.

[37] Three weeks later, Lewan was ejected in the first quarter of a 47–25 victory over the Green Bay Packers after pushing a referee during an altercation with defensive tackle Letroy Guion.

[46] During a 27–20 Week 1 road loss to the Miami Dolphins, Lewan suffered a concussion after a blind side hit by Andre Branch.

[49] During a 13–12 Week 5 loss to the Buffalo Bills, Lewan left the game early due to a foot injury.

[51] The Titans missed the playoffs due to a 33–17 loss to the Colts in the regular-season finale, finishing with a 9–7 record for the third consecutive year.

[53] On July 24, 2019, Lewan announced in a video that he was suspended four games after failing a drug test for a banned substance.

[55] Lewan started all 12 of the Titans' remaining regular-season games, blocking for Derrick Henry as he won the NFL rushing title.

The Titans finished 9–7 for the fourth consecutive year and qualified for the 2019-20 NFL playoffs,[56] making it to their first AFC Championship Game since 2003 where they lost to eventual Super Bowl LIV champions, the Kansas City Chiefs.

[62] Lewan and former teammate Will Compton started a podcast in the summer of 2019 called "Bussin With the Boys" on the Barstool Sports network.

[63] In May 2023, Lewan filed a medical malpractice lawsuit against Dr. James Andrews over an October 2020 surgery to repair a torn ACL that left him with permanent damage.