Born in Limerick, Ireland, Carroll played for Limerick FC was signed for West Ham following his display in an inter-city cup game in Dalymount Park in 1947. In a wide-ranging scouting campaign in the immediate post-world war II period a number of players were recruited by West Ham. Danny McGowan (Shelbourn), Fred Kearns (Shamrock Rovers),Johnny McGowan (Cork United),Brian Moore (Glentoran) and Tommy Moroney (Cork United). Johnny made his debut against Sheffield Wednesday on 30 August 1948.He played only five first team games in his West Ham career in all competitions before a bad knee injury in September '48 finished his season. After two operations he returned home to Limerick to recover and soon after he returned in 1949 he moved to Corby Town.He also played with Sheffield Wednesday and Swansea Town before retiring home to Ireland.Johnny was the only Limerick man to sample first team football for West Ham and on 13 November 1989 on the celebration of the turning on of the new flood lights at Priory Park the then home of Limerick FC a Munster selection played West Ham under management of Lou Macari. Johnny was guest of honor in recognition for his services to Limerick and West Ham.