Brown was born in 2000 and raised in London, Ontario, Canada. He relocated from Canada to Florida as a junior in high school and attended Saint Stephen's Episcopal School in Bradenton, Florida.[1] During the 2016 and 2017 seasons, he was teammates with his identical twin, Sydney Brown, who played safety.[2] He set the school's career rushing record, but received a modest three-star rating by 247Sports.[1]
Brown transferred to Illinois in 2019, joining his identical twin, Sydney, a defensive back for the Illini.[5] Sydney noted: "This is what we dreamt about as kids. Having him come here has been like having a piece of home here in Illinois"[6]
Brown's application for immediate eligibility was initially denied, but granted on appeal in mid-October 2019.[5] After appearing in four games during the 2019 season, he redshirted and retained the year of eligibility.[6] He tallied 18 rushing yards on three carries during the 2019 season.[1]
During the COVID shutdown, Brown and brother Sydney returned to Canada and stayed with their grandmother, converting the garage into a gym.[7] Brown returned to Illinois in the fall and appeared in all eight games for the Illini. On November 14, 2020, he had his first 100-yard game against Rutgers, totaling 134 rushing yards.[8] One week later, he rushed for 115 yards and two touchdowns against Nebraska.[9] For the season, he totaled 540 rushing yards on 104 carries (5.2 yards per carry).[10] At the end of the season, he was selected in fan voting as the Fans Choice Canadian NCAA Player of the Year.[1]
With eligibility not impacted by the 2020 season, Brown remained classified as a sophomore in 2021.[1] On October 2, 2021, he rushed for a career-high 257 yards against Charlotte – the fourth-highest single-game rushing total in Illinois history.[11] Three weeks later, he rushed for 229 yards in the Illini's NCAA-record nine-overtime victory over No. 7 Penn State.[12] His 223 yards was the most ever tallied by an opposing player at Penn State's Beaver Stadium.[1] For the full 2021 season, Brown rushed for 1,005 yards on 170 carries, and his average of 100.5 rushing yards per game ranked second in the Big Ten Conference.[1] Brown was twice named Big Ten Offensive Player of the Week in 2021 and received third-team honors on the 2021 All-Big Ten Conference football team.[1][13]
In the 2022 season opener against Wyoming, Brown rushed for 151 yards and three touchdowns on 19 carries.[14] He was named Big Ten Offensive Player of the Week after the first week.[15] Against Indiana on September 2, he rushed for 199 yards and was selected as the first winner of the Doak Walker National Running Back of the Week award.[16] He then rushed for in excess of 100 yards in each of the next five games: 146 yards against Virginia on September 10;[17] 108 yards against Chattanooga on September 22;[18] 129 yards against Wisconsin on October 1;[19] 146 yards against Iowa on October 8;[20] and 180 yards against Minnesota on October 15.[21] His yardage against Minnesota pushed him over the 1,000-yard mark, making him the first player to reach the mark in 2022 and the third Illinois player to rush for over 1,000 yards in consecutive years.[22] Brown finished second nationally with 1,643 rushing yards.[23][24] He was later awarded the 2022 Jon Cornish Trophy as the top Canadian player in NCAA football.[25]
Brown was ranked the #2 Canadian prospect ahead of the 2023 CFL Draft, where he was drafted in the 7th round (59th overall) by the Montreal Alouettes.[28]
Brown was selected by the Cincinnati Bengals in the fifth round, 163rd overall pick, of the 2023 NFL draft.[29] He was placed on injured reserve on October 28, 2023, with a hamstring injury, and reactivated on November 25.[30]
In Week 14 against the Indianapolis Colts, Brown scored his first NFL touchdown on a 54-yard pass from Jake Browning; he finished the day with 105 total yards on three catches and eight carries.[31]