As a true freshman at Oklahoma in 2017, Sermon played in all 14 games and made three starts. He finished the season with 744 yards on 121 carries with five touchdowns.[4] As a sophomore in 2018, he shared time with Kennedy Brooks, rushing for 947 yards on 164 carries and 13 touchdowns.[5] As a junior in 2019, he played in nine games and had 54 carries for 385 yards and four touchdowns.[6]
Sermon was selected by the San Francisco 49ers in the third round (88th overall) of the 2021 NFL draft.[15] He signed his four-year rookie contract on July 21, 2021.[16]
Sermon entered his rookie season in 2021 as the third-string running back behind Raheem Mostert and fellow rookie Elijah Mitchell. He made his first career start in Week 3, where he rushed for 31 yards and a touchdown with two catches for three yards and another touchdown against the Green Bay Packers.[17] He suffered an ankle injury in Week 12 and was placed on injured reserve on December 4, 2021.[18] He was activated on January 11, 2022.[19] As a rookie, he appeared in nine games and started two. He totaled 41 carries for 167 rushing yards and one rushing touchdown.[20]
Sermon was released by the 49ers on August 31, 2022.[21]
Philadelphia Eagles
On September 1, 2022, Sermon was claimed off waivers by the Philadelphia Eagles.[22] He appeared in two games, Weeks 4 and 5, in the 2022 season.[23]
Sermon was waived/injured by the Eagles on August 29, 2023.[24] He reverted back to injured reserve two days later.[25] On September 15, 2023, the Eagles waived Sermon from injured reserve.[26]
Indianapolis Colts
On September 19, 2023, Sermon was signed to the practice squad of the Indianapolis Colts.[27] He was promoted to the active roster on September 23.[28] He appeared in 14 games for the Colts in the 2023 season. He recorded 35 carries for 160 rushing yards.[29]
On March 14, 2024, the Colts re-signed Sermon to a new contract.[30]