He played college football at Virginia Tech, and was selected by the Minnesota Vikings in the sixth round of the 2014 NFL draft.

Exum attended Deep Run High School in Glen Allen, Virginia, where he participated in football, basketball and track.

He started all 13 games, recording 48 tackles, including 1.5 for loss and led the team with five interceptions.

He capped off his season with an MVP performance in the 2012 Russell Athletic Bowl vs Rutgers, and was also named second-team All-ACC.

[4] In January 2013, Exum suffered a torn ACL and lateral meniscus of his right knee during a pick-up basketball game.

He missed the team's spring practice and fall camp due to the injury, but was cleared to play on October 1, 2013, by surgeon Dr. James Andrews, just under nine months since his initial diagnosis.

[6] Despite being cleared to play, Exum opted not to dress the next two games, but returned to start the next three games before spraining his ankle which caused him to miss the rest of the season, including the Sun Bowl vs. UCLA Exum and his highly touted NFL prospect teammate, Kyle Fuller, also missed the Sun Bowl.

[7] After trading down twice from 148th and 168th, the Minnesota Vikings selected Exum in the sixth round (182nd overall) of the 2014 NFL draft.

Exum was one of just two Vikings defenders to play every snap (64) in the 20–10 win over the Atlanta Falcons in Week 12, and he had a strong day in his first career start (Harrison Smith was inactive with a knee injury) as the Vikings contained wide receiver Julio Jones and the Falcons' fifth-ranked pass offense.

[11] After an injury in mini-camp, Exum went into the 2017 training camp healthy, and spent the first week of practice as a nickel corner after spending his first few seasons as a safety.

[16][17] In Week 4 against Philip Rivers and the Los Angeles Chargers, Exum recorded his first career interception and touchdown.

[24] [25] After an injury ended his 2016 season with the Minnesota Vikings, Exum started recording songs.