Killough began his coaching career as a graduate assistant at
Bowling Green in 2017, where he worked with defensive backs and special teams. After one season he returned to Incarnate Word as an offensive quality control coach. Killough was promoted to inside wide receivers coach and added duties as the Cardinals' recruiting coordinator in 2020. He was briefly the interim head coach after the 2021 season when head coach
Eric Morris left UIW to become the offensive coordinator at
Washington State. Killough was elevated to wide receivers coach and named associate head coach by new head coach
G. J. Kinne. He was hired as Incarnate Word's head coach on December 15, 2022, to replace Kinne after he was hired as the head coach at
Texas State. ==Head coaching record==