He competed in swimming and wheelchair fencing at the Paralympic Games.

Clark enjoyed greater success in wheechair fencing, however.

He won a Paralympic bronze medal as part of Britain's épée team at Heidelberg 1972. 

Four years later, he won a silver medal in the men's épée team 2-5 and bronze in the men's épée individual 4-5 in Toronto.

Clark took his fourth medal at Stoke Mandeville/New York 1984, a bronze in the men’s foil individual 4-5.

He was also a wheelchair basketball player for the Thistle Wheelchair Basketball Club based in Edinburgh and was an active member of Scottish Disability Sport.