Gustavo Rojo was born on 5 September 1924 on a German ship in the middle of the Atlantic Ocean.

[2] His mother was the prominent Spanish author Mercedes Pinto, who emigrated to Uruguay for political reasons.

His two older siblings, Pituka de Foronda and Ruben Rojo, also became actors.

Gustavo's screen debut came as a child actor in the 1938 Cuban film Ahora seremos felices, in which his older sister Pituka had a starring role.

[3] In 1947, he made his Hollywood debut in the film Tarzan and the Mermaids, which starred Johnny Weissmuller and Brenda Joyce.