In Njongmeta's first two seasons in 2019 and 2020, he redshirted and only appeared in one game in which he recorded no statistics.[5] In the 2021 season, Njongmeta totalled four tackles in two games.[6] In week three of the 2022 season, Njongmeta tallied his first career interception, as he helped the Badgers rout New Mexico State 66–7.[7] In week eleven Njongmeta recorded a sack to help end a drive, but Wisconsin ended up losing to Iowa 24–10.[8] In week twelve, Njongmeta notched 2.5 tackles for loss and one sack, as helped the Badgers become bowl eligible by beating Nebraska 15–14.[9] In the Badgers season finale, Njongmeta had a career performance, tallying 12 tackles with 2.5 going for a loss, and 0.5 sack, but Wisconsin fell to Minnesota 23–16.[10] Njongmeta finished his breakout 2022 season with 95 tackles with 11.5 being for a loss, 3.5 sacks, a pass deflection, and an interception.[11] For his performance on the season, Njongmeta was named third team all-Big Ten by the media.[12][13] Ahead of the 2023 season, Njongmeta was named to the watch list for multiple awards: the Bronko Nagurski Trophy, the Rotary Lombardi Award, the Bednarik Award, and the Butkus Award.[14][15][16][17]
Njongmeta signed with the Cincinnati Bengals as an undrafted free agent on May 10, 2024.[21] Njongmeta was among the 53 players to make the Bengals' Week 1 roster.