Spiller attended Klein Collins High School in Spring, Texas.
[8] During the 2020 season, in which he rushed 188 times for 1,036 yards and 9 touchdowns, Spiller was named to the all-SEC Coaches' first team.
[9] On December 14, 2021, after a season in which he rushed 179 times for 1,011 yards and 6 touchdowns, Spiller announced that he would be declaring for the 2022 NFL draft and skipping the 2021 Gator Bowl.
[13] On August 27, 2024, Spiller was waived by the Chargers and re-signed to the practice squad, but released days later.
[14][15] On December 18, 2024, Spiller was signed to the Las Vegas Raiders practice squad.