His family had historically played a prominent role in the island's commercial, political and military affairs.

Marxuach's mother was the granddaughter of José Julián Acosta, a distinguished journalist and a fervent advocate of the abolition of slavery in Puerto Rico.

On June 17, 1928, he joined the Puerto Rico National Guard and received his basic training at Camp Las Casas in Santurce.

During this time period, Marxuach married Margarita Ginorio Dominguez (December 23, 1938) and he earned his master's degree in Botany from the University of Michigan.

As a precautionary measure, the 295th and 296th Infantry Regiments of the Puerto Rican National Guard, founded by Major General Luis R. Esteves, were called into Federal Active Service and assigned to the Puerto Rican Department in accordance with the existing War Plan Orange.

Here he studied the organization and composition of foreign armies, advanced map reading, interrogation of the enemy during war, and evaluation of information.

[10] Marxuach was given the task of organizing the San Juan Municipal Civil Defense and on March 8, 1952, became its first director.

The Civil Defense was established during the Cold War to prepare civilians for a nuclear military attack.

[5] Marxuach held the positions of San Juan municipal legal advisor and director of the city's Civil Defense until April 18, 1957, when he died after a brief sudden illness in his house in Santurce.

The shelter, which is located in a sector of San Juan called Río Piedras, was named the "Colonel Gilberto Marxuach Center" in his honor.