[27] Constituted in March 1942,[28] the 1st Filipino Infantry Battalion was activated in April at Camp San Luis Obispo,[23] to liberate the Philippines.

[1] Colonel Robert Offley was selected as the unit's commanding officer, as he spoke Tagalog and had spent time on Mindoro in his youth.

[39] In November 1943, it paraded through Los Angeles, with Carlos Bulosan, the influential Filipino author of America Is in the Heart, there to witness it.

[42] Soldiers of the Regiment faced discrimination in Marysville while visiting from neighboring Camp Beale, as the local businesses refused to serve Filipinos.

[4][43] This was later remedied by the Regiment's commander, who informed the Chamber of Commerce that they were failing to cooperate with the Army, at which point they changed their business practices.

[44] In April 1944, the Regiment departed California aboard the USS General John Pope for Oro Bay, New Guinea.

[47] Upon arriving at Oro Bay, it was assigned to the 31st Infantry Division, 8th Army to provide area security and continue training.

[48] Some soldiers were then assigned to the Alamo Scouts,[49] the 5217th Reconnaissance Battalion,[50] and to the Philippine Regional Section of Allied Intelligence Bureau.

[51] One example was Second Lieutenant Rafael Ileto, a future Vice Chief of Staff in the Philippines, who led a team in the Alamo Scouts.

[2] By August 1945, operations came to a close[1] due to the Japanese Emperor's decision to end the war following the bombings of Hiroshima and Nagasaki.

[1] Many younger soldiers connected to a culture to which they had previously only had a distant relationship, learning language and customs that were not used or practiced in the United States.

[3] Soldiers of the Regiment who did either not qualify to return to the U.S., either due to having insufficient service points[48] or their being otherwise ineligible,[1] and those who chose to remain in the Philippines,[1] were transferred to 2nd Filipino Infantry Battalion (Separate) in Quezon City.

[1][2] During the war the efforts of Filipino and American defenders during the Battle of Bataan were widely covered by the press,[11] as were the actions of the 100th and 442nd Infantry.