Born in Dublin, Carolan started his career with Home Farm at youth level before moving to Manchester United on 15 February 1956,[1] where he featured in their FA Youth Cup winning team. On 22 November 1958, Carolan made his senior debut against Luton Town. He broke into the first team nine months after the Munich air disaster, which had claimed the lives of eight United players - including his fellow countryman Billy Whelan -[2] and resulted in two other players being injured to such an extent that they never played again.
He played 71 times for United between 1958 and 1960 and won two caps for the Republic of Ireland making his debut on the 1 November 1959.[3]