Jackson was born Sep. 15, 1999 in Plainfield, New Jersey. He grew up in Carmel, Indiana. His father, Jaren Jackson Sr., played 12 seasons in the NBA and won the 1999 NBA title as a member of the Spurs. Jackson Jr.'s mother, Terri Jackson, is the director of operations for the Women's National Basketball Players Association as of 2020. Jackson Jr. attended Park Tudor High School, leading the team to back-to-back Indiana Class 2A state championships in 2014 and 2015. As a prep senior, he played for La Lumiere and led the team to a 29-1 record and the MaxPreps Independent Top 10 National Championship. While at Michigan State, Jackson majored in communications. You can follow Jackson on Twitter @jarenjacksonjr.