Mardner first college football for the Hawaii Rainbow Warriors from 2018 to 2021.[1] He played in only one game in 2018 and was redshirted. He played in 12 games, starting one, in 2019, catching five passes for 169 yards and two touchdowns.[1] Mardner appeared in eight games, starting two, during the COVID-19 shortened 2020 season, recording 11 receptions for 188 yards and one touchdowns. He played in 13 games, starting 10, during the 2021 season, catching 46 catches for 913 yards and five touchdowns.[1]
Mardner transferred to play for the Cincinnati in 2022.[2] He totaled 19 receptions for 218 yards and three touchdowns in five games played.[3]
He transferred to Auburn for his sixth, and final, season of college football in 2023.[4][5] He appeared in four games for the Tigers but did not catch any passes.[3]