 His debut for "Killie" was versus Partick Thistle at Rugby Park in the Scottish League Cup on 9 August 1975, he scored Kilmarnock's first goal in the Premier Division format on 4 September 1976 at home to Motherwell, and his final game was also at home versus Ayrshire derby rivals Ayr United in a league match on 3 May 1986.He left the club and retired from professional football at the age of 29 to join Strathclyde Police before reaching their upper recruitment age limit; despite ending his career early, he is ranked 11th on Kilmarnock's all-time appearance list, having played in 436 matches across 11 seasons in the three major competitions.Clarke's two Scottish League XI caps were versus Italy B in 1978 and League of Ireland in 1980.