Departing New York 29 September 1937, Cummings arrived at San Diego 28 October to join the Battle Force. She participated in the fleet problem in Hawaiian waters in April 1938 and a Presidential Fleet Review at San Francisco in July. In 1939, the exercises were held in the Canal Zone and the Caribbean from January to April. Returning to San Diego 12 May 1939, Cummings participated in flotilla and fleet training, and served as plane guard for the carriers Yorktown (CV-5) and Lexington (CV-2). When the security patrol was begun on the west coast in 1940, Cummings served on it intermittently, while continuing to conduct exercises in antiaircraft and submarine tactics, and target practice.
Cummings was based at Pearl Harbor from 26 April 1940. Except for a west coast overhaul and a cruise to Tutuila, Samoa; Auckland, New Zealand; and Tahiti between 4 March and 3 April 1941, Cummings remained in Hawaiian waters conducting patrols and constantly exercising and drilling.
When the Japanese attacked Pearl Harbor on 7 December 1941, Cummings weathered bombs that fell ahead and astern, receiving only minor casualties from fragments, and sortied on patrol almost immediately. From 19 December 1941 to 4 May 1942 Cummings escorted convoys between Pearl Harbor and San Francisco, then sailed between Suva, Fiji Islands, and Auckland, New Zealand., from 9 June to 13 August on similar duty.
After overhaul at San Francisco, Cummings escorted a convoy to Nouméa, and Wellington, New Zealand in November 1942; then began patrol and escort missions for the Guadalcanal operation from bases at Espiritu Santo and Nouméa until 17 May 1943 when she sailed to Auckland, New Zealand, for brief overhaul. Returning to Nouméa 4 June, Cummings screened transports to Auckland in July, and then served at Éfaté from 5 August until 4 September.
Overhauled on the West Coast again, Cummings joined TF 94 to patrol off Adak, Alaska, between 1 and 16 December before returning to Pearl Harbor 21- December. Assigned to the Fifth Fleet, she sortied on 19 January 1944 for the Marshalls operations, accompanying the carriers for air strikes on Wotje and Eniwetok until 21 February. Cummings sailed from Majuro 4 March for Trincomalee, Ceylon, where she rendezvoused 31 March with British ships for exercises. She sailed 16 April with British Force 70 to screen during air strikes on Sabang, Sumatra, on 19 April, and then returned to Ceylon until 6 May when she cleared for Exmouth Gulf, Australia. With British Force 66, she sortied 15 May for air strikes on Soerabaja, Java, then left the British forces and returned by way of Sydney to Pearl Harbor.
Arriving at San Francisco 7 July 1944, Cummings sailed 21 July to escort President F. D. Roosevelt embarked in Baltimore (CA-68) to Pearl Harbor, Adak and Juneau. The President and his staff came aboard 8 August for transportation to Seattle and upon arrival there, 12 August, President Roosevelt broadcast a nationwide address from the forecastle of Cummings.
Departing Seattle 13 August 1944, Cummings joined TG 12.5 at Pearl Harbor for an air strike and shore bombardment of Wake Island on 3 September. With the Third Fleet, she joined in the bombardment of Marcus Island on 9 October, then screened the escort carriers as they launched the supporting air strikes on Luzon, Cebu, Leyte, Samar and Negros, during the Leyte landings, and gallantly engaged the Japanese in the decisive Battle for Leyte Gulf. She took part in the bombardment of Iwo Jima on 11 and 12 November, and then returned to Saipan 21 November for local duty. She interrupted this duty to join in the repeated strikes on Iwo Jima from 8 December 1944 to 19 March 1945 when she supplied fire support for the invading troops. She was stationed off Iwo Jima, occasionally escorting convoys to Saipan and Guam until the end of the war. Her duties included local convoy escort and control duty, and the important air-sea rescue work that accompanied the intensified strikes on Okinawa and the Japanese home islands. She supervised the occupation of Haha Jima on 9 September, and then sailed from Iwo Jima 19 September for San Pedro, Calif., Tampa, Fla. and Norfolk. Cummings was decommissioned 14 December 1945 and sold 17 July 1947.
Cummings received seven battle stars for service, during World War II.