Cushing served on the neutrality patrol off Rose Bank, New York until 28 December 1915. She sailed to the Caribbean for fleet maneuvers on 4 January 1916, and after joining in fleet tactical exercises off Portland, Maine and gunnery exercises off Norfolk, reported to Newport on 27 September to test torpedoes at the Naval Torpedo Station. She returned to the Caribbean for fleet exercises between January and March 1917.
Cushing put to sea from New York 15 May 1917 and arrived at Queenstown, Ireland on 24 May for duty in the war zone. She patrolled off the Irish coast, meeting and escorting convoys of merchant ships and troop transports to British ports and the French coast. Enemy submarines menaced the area and Cushing fought them unrelentingly, as well as performing rescue work on the ships that were sunk by U-boats. On 4 June she picked up 13 men adrift in a small boat, survivors of Italian brig Luisa. She joined Perkins (Destroyer No. 26) in rescuing survivors of the torpedoed and sinking British merchant ship SS Tarquah 7 July, and the next day, responding to an SOS from SS Onitsha who was being chased by an enemy submarine, picked up 54 survivors of SS Obuasi which had already been sunk.
On 16 July, she escorted SS Tamele to safety after the merchantman had received five hits, and the same day fired on two submarines at extremely long range following their attack on the Italian merchant vessel SS Lamia, from which she rescued 27 survivors. Five survivors from the British SS Vienna were saved 12 September after being adrift for two days. On 26 November, when SS Crenella was torpedoed, Cushing stood by, giving damage control assistance which kept the merchantman from sinking and then escorting her into Queenstown. Cushing rejoined her convoy the next day.
Continuing her convoy escort and patrol duty, Cushing on 23 April 1918 dropped 15 depth charges on U-104, damaging her severely. HMS Jessamine sank U-104 later the same day.
Cushing operated from Brest, France, after 11 June 1918 escorting 11 troop convoys through the danger zones to French ports in which she made two depth charge attacks. She also towed Murray (Destroyer No. 97), disabled when she grounded on the rocks in the Harbor of L’Abenach on 3 December, into the safety of Brest.
Cushing cleared Brest 21 on December 1918 with one of the outstanding records for World War I service. Arriving at New York on 6 January 1919, she was placed in reduced commission from 1 July 1919 and transferred to the Philadelphia Navy Yard 6 April 1920. Cushing was decommissioned 7 August 1920, sold 30 June 1936, and scrapped in accordance with the London Treaty for the limitation of naval armaments.