She graduated in 1943 with a gold medal and made her debut the same year in Eva Franco's El Carnaval del Diablo ("The Carnival of the Devil").

[4] In 1947, following the election of Juan Perón, Gallo left Argentina for Chile and, eventually, Italy.

After graduating in 1952, she appeared in Dialogues of the Carmelites [es] at the Piccolo Teatro Della Città Di Roma and starred in the world premiere of Diego Fabbri's Processo a Gesù ("The Trial of Jesus") at the Piccolo Teatro di Milano.

Returning to Argentina in 1958, she performed in many successful plays including The Dog in the Manger, with Alfredo Alcón and Osvaldo Bonet, and Les Troyens, which received the Critics Award from the National Endowment for the Arts.

Television performances include Romeo y Julieta, Perla Negra ("The Black Pearl") (for both of which she received two separate Martin Fierro Awards for her performances), and, more recently, 22 El Loco alongside Adrián Suar, where she played the grandmother of the protagonist.