Gallo was a terrorist affiliated with SPECTRE. During the 2015 Day of the Dead Festival in Mexico City, Gallo met up with assassin Marco Sciarra to discuss their plans for a stadium bombing later in the day. Sciarra stated that his next step was to pay a visit to the "Pale King." However Gallo spotted James Bond pointing a rifle at them from an adjacent roof. Although Bond quickly shot and killed Gallo and his accomplices, Sciarra made his escape into the busy streets, pursued by Bond, who eventually caught up to and killed Sciarra by kicking him out of a helicopter.