Completed in May 1940. On 22 Aug 1942, USS Buck (DD 420) (LtCdr L.R. Miller, USN) was rammed by the British liner Awatea in dense fog while escorting the convoy AT-20 from Halifax to Scotland. The impact on starboard side aft broke her keel, damaged both screws and seven men were lost. The destroyer was taken in tow by USS Cherokee (AT 66) and after four days reached Boston, where she was repaired until November 1942. In 1943 the destroyer participated in the landings of Sicily and Salerno. On 3 August 1943, while escorting a convoy of six Liberty ships from Sicily to Algeria, USS Buck (DD 420) (LtCdr M.J. Klein, USN) attacked and sank the Italian submarine Argento off Pantellaria in 36°52N/12°08E and took 45 men of her crew as prisoners.

USS Buck (DD 420) received three battle stars for her WWII service.

At 00.36 hours on 9 October 1943, U-616 fired a Gnat acoustic torpedo from the stern torpedo tube at USS Buck (DD 420) (LtCdr M.J. Klein, USN) on patrol off the Salerno beachhead about 50 miles south of Capri, Italy. The destroyer had picked up a radar contact and approached it at 25 knots, preparing a full pattern of depth charges, when the torpedo struck the starboard bow after a running time of 4 minutes 15 seconds. The explosion apparently ignited the forward magazine as two detonations occurred almost simultaneously, blew off the bow and wrecked the navigating bridge, killing the commander and all other officers on watch except one who was blown overboard. The crew tried to set the depth charges on safe but the destroyer sank with the stern raising high out of the water within four minutes after being hit. The starboard charges could not be secured and exploded after the ship sank, killing or wounding many men swimming or clinging to debris and rafts. As no distress signal were sent the loss of USS Buck remained unnoticed until a C-47 aircraft spotted the survivors the next morning and dropped three rubber life rafts. However, the first rescue vessel only reached the position more than 17 hours after the sinking. USS Gleaves (DD 423) (LtCdr B.L. Gurnette, USN) picked up 64 survivors and four bodies, but four men died shortly after being rescued and four more in a hospital ashore during the following days. USS Plunkett (DD 431) (Cdr E.J. Burke, USN) picked up five bodies and 13 survivors of whom one died aboard. One survivor was picked up by HMS Delhi (D 74) (Capt A.T.G.C. Peachey, RN) and the remaining survivors were picked up by HMS LCT-170. Almost all survivors were injured and had to be hospitalized when they were landed in Palermo on 10 October.