After redshirting his first year at Oklahoma State in 2017, Hubbard played in 13 games in 2018 and had 740 rushing yards on 124 carries with seven touchdowns.[6][7] He returned as Oklahoma State's starting running back in 2019 and had a stellar year rushing for 2,094 yards on 328 carries and 21 touchdowns.[8][9] Despite speculation that he would declare for the 2020 NFL draft after this season, Hubbard announced that he would return to school for his redshirt junior year.[10] He was awarded the Jon Cornish Trophy as the top Canadian in NCAA football for the season.
In June 2020, Hubbard threatened to boycott the football team and any affiliation with the university after a photo surfaced showing Oklahoma State head coach Mike Gundy wearing a T-shirt promoting the One America News Network (OAN), a far right news channel. Gundy subsequently issued an apology, saying he was disgusted by OAN's coverage of the Black Lives Matter movement.[11] Hubbard eventually apologized for the way he handled the situation.[12]
Hubbard was selected by the Carolina Panthers in the fourth round (126th overall) of the 2021 NFL draft.[15] He was also selected by the Calgary Stampeders in the fifth round (43rd overall) of the 2021 CFL Draft before signing a four-year contract, worth $4.2 million, with the Panthers on May 6, 2021.[16][17] Hubbard made his NFL debut in Week 1 of the 2021 season against the New York Jets. In Week 5, against the Philadelphia Eagles, he had 24 carries for 101 rushing yards in the 21–18 loss.[18] He finished the 2021 season with 172 carries for 612 rushing yards and five rushing touchdowns to go along with 25 receptions for 174 receiving yards and one receiving touchdown in 17 games and ten starts.[19]
In Week 16 of the 2022 season, Hubbard had 12 carries for 125 rushing yards in a 37–23 victory over the Detroit Lions.[20] He finished the 2022 season with 95 carries for 466 rushing yards and two rushing touchdowns to go along with 14 receptions for 171 receiving yards in 15 games and two starts.[21]
At the beginning of the 2023 season, Hubbard was listed as second on the depth chart behind new addition Miles Sanders. In Week 1, Hubbard recorded nine carries for 60 yards. Hubbard assumed the starting position in Week 6 against the Miami Dolphins when Sanders was ruled out and carried the ball nineteen times for 88 yards and a touchdown, the best performance by a Panthers running back in the season. Despite Sanders' return, Hubbard continued in the starting role. In Week 12 against the Tennessee Titans, Hubbard had 14 carries for 45 yards and a touchdown, as well as reeling in 5 catches for 47 yards as the Panthers went on to lose 17–10. The following week against the Tampa Bay Buccaneers, Hubbard ran 25 times for 104 yards and 2 touchdowns in the 21–18 loss. In the Panthers' Week 17 loss to the Jacksonville Jaguars, Hubbard reached 1,000 scrimmage yards for the first time in his NFL career.[22]
On November 7, 2024, the Panthers signed Hubbard to a four-year, $33.2 million extension, with $15 million guaranteed.[23] In the Panthers' Week 12 loss to the Kansas City Chiefs, Hubbard reached 1,000 scrimmage yards for the second straight season.[24] In Week 16, Hubbard ran for 152 yards and two touchdowns in a 36-30 overtime win over the Arizona Cardinals, earning NFC Offensive Player of the Week.[25] On December 28, Hubbard was place on injured reserve with knee and calf injuries, ending his season. In 15 starts for Carolina, he totaled 1,195 rushing yards, 171 receiving yards and 11 touchdowns.[26]