He played college football at Missouri and was selected by the Las Vegas Raiders in the fourth round of the 2021 NFL draft.
Gillespie grew up in Ocala, Florida and attended Vanguard High School.
[2] He committed to play college football at Missouri over offers from Iowa State, Marshall, New Mexico and Troy.
[7] Gillespie was selected by the Las Vegas Raiders in the fourth round, 143rd overall, of the 2021 NFL draft.
[12] He entered his rookie season as the backup strong safety and mostly played in special teams.
On August 16, 2022, Gillespie was traded to the Tennessee Titans for a conditional 2024 seventh-round pick.