Born on the island of Jersey, Campbell was a sporty child who progressed through youth competitions to compete internationally in athletics for Britain. As a middle-distance runner Campbell competed in the 400 meters and 800 metres. He reached the second round of the 400m in 1968 and broke the British record in qualifying for the 800m in 1972, though running with an injury he did not progress out of the first round. He also competed for England at the 1970 and 1974 Commonwealth Games. He subsequently answered an advert calling for trialists for the British bobsleigh team and, having successfully competed in these, was selected for the 1976 four-man bob team, where Britain finished 13th.