Spillum attended Chanhassen High School where he played football, baseball and also lettered in track and field.
After moving from wide receiver to quarterback for his senior year, he led the Storm to an undefeated regular season and the third round of the Class 5A state tournament.
Spillum was selected to the Minnesota Football Showcase South Roster for the All-Star Game as a defensive back and was rated as a two-star recruit by 247Sports.com.
[2] In his time at Coastal Carolina, he was a two-time All-Sun Belt third-team selection and was All-Conference Honoree from Phil Steele in both 2020 and 2021.
In the 2021 Cure Bowl win, he made a remarkable play, tackling his own teammate after a recovered forced fumble to keep ball possession.