Playing for Conwell-Egan Catholic High School in Fairless Hills, Pennsylvania, Slaton made the varsity football team as a freshman. He was named captain as a senior, was the most valuable player of the Philadelphia Catholic League, and was a four-year all-conference selection. As a senior, he rushed for 1,836 yards and 26 touchdowns. He was a first team all-state as a junior and senior. He rushed for more than 6,000 career yards and 73 touchdowns, setting five school records. Slaton was invited to, but did not participate in, the annual Big 33 Football Classic.