While at Tulane, Hilliard rushed for 2,948 yards and 30 touchdowns and caught 70 passes for 740 yards and four touchdowns over the course of four seasons (47 games).[3] As a senior, Hilliard was third in the American Athletic Conference (AAC) with 1,091 rushing yards and rushed for 12 touchdowns and was named second-team All-AAC.[4]
Hilliard was promoted to the Browns' active roster on October 9, 2018.[6] He made his NFL debut on October 14 against the Los Angeles Chargers, returning one kick for 31 yards and recording a tackle on special teams.[7]
Hilliard finished his rookie year with nine receptions for 105 yards to go along with 11 kicks for 264 yards (24.0 average) and three special teams tackles in 11 games and no starts.[8]
2019 season
During the season-opening 43–13 loss to the Tennessee Titans, Hilliard scored his first touchdown on a four-yard run, the first carry of his NFL career.[9] Hilliard was placed on injured reserve on December 24, 2019.[10]
Hilliard finished his second professional season with 13 carries for 49 yards and two touchdowns to go along with 12 receptions for 92 yards and led the team with 421 kickoff return yards and 107 punt return yards in 14 games and no starts.[11]
2020 season
Hilliard was tendered by the Browns for the 2020 season.[12] He was placed on the reserve/COVID-19 list on July 26, 2020,[13] and activated from the list nine days later.[14]
Hilliard was waived on September 5, 2020.[15] The Browns re-signed him to their practice squad the next day.[16] Hilliard was promoted to the active roster on September 30, 2020.[17] He was waived by the team on December 13, 2020.[18]
Houston Texans
On December 15, 2020, Hilliard was claimed off waivers by the Houston Texans.[19] He signed a contract extension with the team on March 1, 2021,[20] which was reported by Ian Rapoport of NFL Network as a one-year, $1.25 million extension.[21] On August 16, 2021, HIlliard was waived with an injury designation by the Texans and placed on injured reserve.[22] He was released on August 19.
Tennessee Titans
2021 season
On October 27, 2021, Hilliard was signed to the Titans practice squad.[23] After being elevated to the active roster, he rushed for 35 yards on seven carries, caught eight passes for 47 yards, and returned three kickoffs for 65 yards in a Week 11 22–13 loss to the Texans. After the game, Hilliard was reverted back to the practice squad. On November 23, 2021, the Titans signed Hilliard to the active roster.[24] During a 36–13 Week 12 road loss to the New England Patriots, Hilliard had 12 carries for 131 yards and a 68-yard touchdown.[25] Both he and fellow running back D'Onta Foreman rushed for over 100 yards in that game, the first time the Titans had two 100-yard rushers in a game since Chris Johnson and LenDale White in 2008.[26]
Hilliard finished the 2021 season with 56 carries for 350 yards and two touchdowns to go along with 19 receptions for 87 yards and eight returns for 177 yards in eight games and five starts.[27]
2022 season
On March 19, 2022, Hilliard re-signed with the Titans.[28] He was placed on injured reserve on December 17, 2022, following an in-game neck injury.[29] He finished the 2022 season with 22 carries for 145 yards to go along with 21 receptions for 177 yards and four touchdowns, and three returns for 27 yards in 12 games and one start.[30] He was not resigned by the Titans during the 2023 off-season.