After playing at Shawnee Heights High School, Ballentine played college football at Division II Washburn, Ballantine played in 46 games after almost quitting the team in the summer before his freshman year. He primarily played on defense but also served as the team's kick returner and blocked four field goals. Ballentine won the Cliff Harris Award after the conclusion of his senior season, which is given annually to the nation's top small college defensive players. He was also named a 2018 second-team AFCA All-American.
Ballentine was born in Montego Bay, Jamaica and moved to the United States at six years of age. While at Shawnee Heights and Washburn, Ballentine ran track while playing football, setting Ichabod records for various indoor and outdoor sprinting events.
In the early morning hours of April 28, the Sunday following the 2019 NFL Draft, Ballentine was injured in a shooting in Topeka while he was attending an off-campus party. Ballentine's college roommate and defensive backfield teammate Dwane Simmons was killed in the shooting.