World War II

Griswold commanded the 29th Infantry Regiment from September 1939 to October 1940. The 29th was the primary training regiment permanently billeted at the Infantry School at Fort Benning, Georgia; under Griswold's command, the first Parachute Test Platoon was organized out of the 29th, as well as its ersatz successor, the original 501st Parachute Battalion. Griswold was promoted to brigadier general in October 1940 and became Commanding General of the Infantry Replacement Training Center at Camp Croft. Promoted to major general in August 1941, he commanded 4th Infantry Division.^[1]

From April 1943, Griswold was Commanding General of the XIV Corps, which fought in New Georgia, Bougainville and in the Philippines. It was for his service during this period that he was awarded the Navy Distinguished Service Medal, the citation for which reads:

The President of the United States of America takes pleasure in presenting the Navy Distinguished Service Medal to Major General Oscar Woolverton Griswold (ASN: 0-2883), United States Army, for exceptionally meritorious and distinguished service in a position of great responsibility to the Government of the United States while serving as Commanding General, XIV Corps with additional duty as Commander, Bougainville Landing Forces from 15 December 1943 to 5 June 1944. During this period, Major General Griswold displayed exceptional qualities of forceful leadership in the execution of the many offensive operations carried out by his command under extremely difficult terrain and weather conditions. His efficient coordination of the activities of the Army with the Navy and Allied units, enabled our forces to exert their greatest strength against the Japanese and administer a series of crushing defeats. Major General Griswold, through his initiative and broad understanding of combined operations, contributed materially to the neutralization of the last and most formidable Japanese stronghold in the Solomon Islands and to the continued success of the Allied campaign in the South Pacific. His conduct throughout was in keeping with the highest traditions of the United States Military Service.

He was promoted to lieutenant general in early 1945,^[1] and continued to serve in the Pacific theater under Douglas MacArthur during the Battle of Manila in February 1945. Griswold was the top ground commander only under MacArthur and Krueger during that battle, which was the largest urban warfare American troops ever participated in up to that point; Griswold's XIV Corps, in their bitter and bloody fight for Manila, consisted of the 1st Cavalry Division, the 37th Infantry Division, and the 11th Airborne Division. In June 1945, General of the Army MacArthur nominated Griswold to command the Tenth United States Army following the death of Lieutenant General Simon Bolivar Buckner, Jr. in the Battle of Okinawa. However, he was passed over in favor of General Joseph Stilwell.^[4]