In 1942, Japanese imperial forces entered and occupied the town of Santa Cruz.
In 1945, at the beginning of the Battle of Marinduque, Filipino troops of the 5th Infantry Division of the Philippine Commonwealth Army came to Santa Cruz together with the guerrilla units of the Marinduque Revolutionary Army. Marinduque fought the battles against attacks from the Japanese imperial forces in the Second World War.
Republic Act No. 204, approved May 28, 1948, converted the sitios of Angas of the barrio of Tagum, Biga of the barrio of Alobo, Kamandungan of the barrio of Lusok, Kilokilo of the barrio of San Antonio, and Makulapnit of the barrio of Devilla to regular and independent barrios.
In 1953, the sitio of Baguidbirin was converted into a barrio.