McKoy finished seventh in the hurdles at the 1988 Summer Olympics in Seoul, as he hit a number of hurdles in the final. His compatriot Ben Johnson tested positive for banned substances at the Games. Over the course of the Dubin Inquiry, McKoy was another of Charlie Francis's trainees to admit to doping and he was banned for two years.
McKoy had emigrated to Austria over the course of his drugs ban and he consequently obtained Austrian citizenship in 1994. He spent the last years of his career competing for his adopted country and set an Austrian record of 13.14 seconds in the 110 m hurdles.
He has since returned to Toronto, where he now works as personal athletic trainer and therapist. He is an older cousin to the an athlete in Guyana, Kevin Parker who runs marathons.