The 25th DIVARTY first entered combat two months after activation on 7 December 1941, when the Imperial Forces of Japan conducted a surprise attack on US military installations on Oahu, HI.

First arriving to Guadalcanal in late 1942, 25th DIVARTY supported combat operation beginning in January 1943, participating in the seizure of Kokumbona and the reduction of the Mount Austen Pocket in some of the bitterest fighting of the Pacific campaign.

Throughout the 160 days of sustained combat in the Philippines, the 90th FA BN fired over 42,000 rounds in support of the 25th Infantry Division.

25th DIVARTY fires supported the first offensive actions by the division with the capture of the Yechon Road Junction on 20 July 1950.

25th DIVARTY was designated Regional Command East, which comprised 16 provinces in eastern Afghanistan along the Pakistan border.