Wainwright commanded American and Filipino forces during the Japanese invasion of the Philippines, for which he received a Medal of Honor for his courageous leadership.

In May 1942, on the island stronghold of Corregidor, lacking food, supplies and ammunition, in the interest of minimizing casualties Wainwright surrendered the remaining Allied forces on the Philippines.

[1] In 1929, he was promoted to lieutenant colonel and graduated from the Command and General Staff School, Fort Leavenworth, Kansas, in 1931, and from the Army War College in 1934.

[7] As the senior field commander of Filipino and US forces under General Douglas MacArthur, Wainwright was responsible for resisting the Japanese invasion of the Philippines, which began in December 1941.

On 8 December 1941, he commanded the North Luzon Force, comprising three reserve Filipino divisions and the 26th Cavalry Regiment (Philippine Scouts).

[8] Retreating from the Japanese beachhead of Lingayen Gulf, Allied forces had withdrawn onto the Bataan Peninsula and Corregidor by January 1942, where they defended the entrance to Manila Bay.

Due to lack of supplies (mainly food and ammunition)[11] and in the interest of minimizing casualties, Wainwright notified Japanese General Masaharu Homma he was surrendering on 6 May.

Some soldiers considered Wainwright's surrender to have been made under duress, and ultimately decided to join the guerrilla movement led by Colonel Wendell Fertig.

Wainwright was then held in prison camps in northern Luzon, Formosa, and Liaoyuan (then called Xi'an and a county within Manchukuo) until he was rescued by the Red Army in August 1945.

[citation needed] Wainwright was the highest-ranking American POW, and, despite his rank, his treatment at the hands of the Japanese was no less unpleasant than that of most of his men.

He witnessed the Japanese surrender aboard the USS Missouri on 2 September and was given one of five pens (along with British Lieutenant General Arthur Percival) that MacArthur used to sign the document.

[14] Together with Percival, he returned to the Philippines to receive the surrender of the local Japanese commander, Lieutenant-General Tomoyuki Yamashita.

On 7 September, Wainwright would oversee the ceremony which led to the Japanese Instrument of Surrender documents being exhibited at the National Archives.

[19] On 11 January 1946, he was named commander of the Fourth Army at Fort Sam Houston, Texas, filling the vacancy left by the 21 November 1945 death of Lieutenant General Alexander Patch.

[26] About 1935, Wainwright was elected a Hereditary Companion of the Military Order of the Loyal Legion of the United States (insignia number 19087) by right of his grandfather's service in the Union Navy during the Civil War.

At the repeated risk of life above and beyond the call of duty in his position, he frequented the firing line of his troops where his presence provided the example and incentive that helped make the gallant efforts of these men possible.

The final stand on beleaguered Corregidor, for which he was in an important measure personally responsible, commanded the admiration of the Nation's allies.

[31]General Wainwright was presented the Medal of Honor in an impromptu ceremony when he visited the White House on 10 September 1945; he was not aware that he was there to be decorated by President Harry S. Truman.