Juan Pablo Bennett was born in La Serena, the son of Charles (Carlos) Bennett Stacey and Buenaventura Argandoña Barraza. In 1903, he married Carlota Agacio Batres, with whom he had five children: Antonio, Maria Luisa, Juan, Carlota and Jenny. He had a brilliant career in the army. In 1909 he was sent as military attaché to the Chilean embassy in Berlin. In 1924, he was named Minister of War and Navy, by President Arturo Alessandri.