 Farrell was born and raised in the Convent Road area of Dalkey and was educated at Harold Boy's National School and the Christian Brothers in Dún Laoghaire, which he won a scholarship to.He was playing football with Cabinteely Schoolboys when spotted by a Shamrock Rovers scout and subsequently joined Rovers on his 17th birthday in August 1939.Among his early team-mates was the veteran Jimmy Dunne.