McCullough attended John Muir High School in Pasadena, California where he was one of the top sprinters in the state. Along with Obea Moore, he led his team to a CIF State title in the 4×100 relay and was favored to win the state title in the sprint events. However, he suffered an injury while competing in the 100-meter final forcing him to pull out of the race.[3][4] Despite this setback, his team still holds the meet record at the prestigious Arcadia Invitational.