Domínguez was discovered during a match by the cofounder of the famous Club River Plate, Carlos Peucelle, who persuaded Dominguez to begin to train at River Plate in March 1946. He was seventeen years old when he was discovered by delegates of the Racing Club of Avellaneda and he was signed immediately.
In 1957 Domínguez signed for Real Madrid in Spain. After several successful seasons with the club, he returned to South America where he played for River Plate and Vélez Sarsfield in Argentina, and then CA Cerro, Nacional in Uruguay and Flamengo in Brazil.
International career
In 1951 he won the Panamerican Championship playing for the Argentina national football team; to which he'd belonged for 12 years, from 1951 to 1963. He was chosen Best America's Goalkeeper for two consecutive seasons, in 1956 and 1957 and was part of the triumphant team that claimed the 1957 Copa América title.