He played college football for the Texas Longhorns where he twice a second-team all-Big 12 selection and was the 2011 Big 12 Newcomer of the Year.
He was signed by the St. Louis Rams as an undrafted free agent in 2015, and has also played for Miami Dolphins.
[7] Brown chose the University of Texas over Oklahoma, Florida State, Alabama, Notre Dame, and Stanford.
[8] Brown started the season third on the depth chart behind running backs Fozzy Whittaker and Cody Johnson.
[11] On September 17, Brown had his first 100-yard game as he ran for 110 yards on 22 carries and a 16-yard touchdown as he helped the Longhorns defeat the UCLA Bruins 49–20.
After the injury, Brown's performance declined, rushing for only 33, 39, and 35 yards against Kansas State, Texas A&M, and California, respectively.
[17][18][19] Brown still finished the season as the Longhorns' leading rusher with 742 yards on 172 carries and 5 touchdowns.
Brown shared the Longhorns backfield with Johnathan Gray and Joe Bergeron in the 2012 season.
[44] On January 3, 2016, in the regular season finale, he made his NFL debut and had four carries for 17 yards in a 19–16 loss to the San Francisco 49ers.
[48] On September 10, 2017, in the 46–9 victory over the Indianapolis Colts in the season opener, Brown recorded his first career touchdown on a three-yard rush in the fourth quarter.
[50] He earned his first career start in Week 17 in place of Gurley after the Rams decided to rest their starters in preparation for the playoffs.
[55] Without Brown, the Rams reached Super Bowl LIII where they lost 13–3 to the New England Patriots.
[58] Three days later, the Rams officially matched the Lions offer, signing Brown to a two-year, $3.3 million contract.
[59] In Week 1 of the 2019 season against the Carolina Panthers, Brown rushed 11 times for 53 yards and two touchdowns as the Rams won 30–27.
[61] In Week 1 of the 2020 season, Brown was inserted as the starter after Gurley signed with the Atlanta Falcons.
He scored the first touchdown in SoFi Stadium history with a one-yard run in the 20–17 victory over the Dallas Cowboys.