King attended East English Village Preparatory Academy in Detroit, Michigan. He played defensive back and running back. During his career he set a Michigan high school record with 29 interceptions. He also set a school record for career rushing yards and had 2,360 as a senior. King was rated by Rivals.com a three-star recruit and committed to the University of Iowa to play college football.
As a true freshman at the University of Iowa in 2013, King appeared in all 13 games and made 12 starts. He was the first true freshman to start at defensive back for Iowa since 2002. He started all 13 games his sophomore year in 2014 and had 64 tackles and three interceptions. King returned as a starter his junior year in 2015. He also became Iowa's punt and kick returner. After a terrific junior season in which he had 43 tackles, and a Big-Ten high 8 interceptions, King was named a consensus first-team All-American and won the 2015 Jim Thorpe Award, which is given to the best defensive back in all of college football. Despite being projected as an early-round pick in the 2016 NFL Draft, King announced that he would return to Iowa for his senior season. On November 29, 2016, King was name First Team All-Big Ten for the second season in a row. He was also named a 2016 AP Second-Team All-American.
|Year||Team||GP||Tackles||For Loss||Passes Def||Int||FF|
|Ht||Wt||Arm length||Hand size||40‑yd dash||10-yd split||20-yd split||20‑ss||3‑cone||Vert jump||Broad|
|5 ft 10 in|
|31 1⁄8 in|
|9 5⁄8 in|
|All values from 2017 NFL Combine.|
|Year||Team||GP||COMB||TOT||AST||SACK||FF||FR||FR YDS||INT||IR YDS||AVG IR||LNG||TD||PD|