Shea spent 15 more days completing her fitting-out. She then loaded ammunition at Earle and Bayonne, New Jersey, returned briefly to New York and departed for her shakedown cruise on 21 October 1944. She completed shakedown training at and around Great Sound Bay, Bermuda, and was underway for Norfolk, Virginia, on 16 November. Shea’s crew underwent a month of further training in the Norfolk area before embarking, 13 December, for Brooklyn, New York, arriving the next day.

From Brooklyn, Shea moved on to San Francisco Bay, California. Sailing with TG 27.3, she transited the Panama Canal, 20–22 December, and made San Francisco on the last day of 1944. Four days later, she was underway for Pearl Harbor, Hawaii, and 13 more days of training exercises. Another round of training complete, she steamed out of Pearl Harbor bound for Eniwetok Atoll in the western Pacific, arriving on 2 March. After 17 days in the vicinity of Eniwetpk, her crew engaged in still more of the perennial training exercises. Shea departed for Ulithi Atoll on the first leg of her cruise into the real war at Okinawa.

On 19 March 1945, she sailed from Ulithi and joined TG 52.3. By 24 March, Shea was off Okinawa helping prepare the way for the 1 April invasion. While her primary mission was to protect and assist the minesweepers clearing the area of enemy mines, she also stood radar picket duty all around Okinawa. During the period 24 March–4 May, she was constantly fending off Japanese air attacks and guarding against enemy submarines. Moreover, she probably sank or severely damaged at least one submarine and, on 16 April, in the space of 10 minutes, splashed no less than six enemy planes.

On the morning of 4 May 1945, Shea was en route to radar picket duty 20 miles NE of Zampa Misaki, Okinawa. She arrived just after 0600, having encountered two Japanese aircraft along the way, firing on both and possibly splashing one. Upon receipt of reports indicating the approach of large Japanese air formations, Shea’s crew went to General Quarters. Soon thereafter, a “considerable smoke haze blew over the ship from the Hagushi beaches” and “visibility was at a maximum 5.000 yards.” At 0854 a single enemy Betty was sighted six miles distant; and, four minutes later, one was shot down by Shea-directed CAP. At 0859, five minutes after the initial sighting, a lookout spotted a Japanese baka bomb on Shea’s starboard beam, closing the ship at better than 450 knots. Almost instantaneously, the baka crashed Shea “on the starboard side of her bridge structure, entering the sonar room, traversing the chart house, passageway and batch, and exploding beyond the port side on the surface of the water. Fire broke out in the mess hall, C.I.C., chart house, division commander’s stateroom, #2 upper handling room, and compartment A-304-L.”

Shea lost all ship’s communications, 5-inch sun mounts numbers 1 and 2 were inoperative; and the forward port 20 millimeter guns were damaged. The main director was jammed and the gyro and computer rendered unserviceable. One officer and 26 men were killed, and 91 others were wounded to varying degrees.

With repair parties and survivors from damaged areas scurrying about, helping the wounded and fighting fires, Shea, listing 5 degrees to port, began limping off to Haeushi and medical assistance. She arrived there at 1052; her most seriously wounded crew members were transferred to Crescent City (APA 21) ; and the bodies of the 27 dead were removed for burial on Okinawa. Shea then resumed her limping, this time to Kerama Retto anchorage. At Kerama Retto, she underwent repairs and disgorged all but 10 percent of her ammunition. In addition, much of her gear, particularly radar and fighter direction equipment, was transferred to DesRon 2 for distribution to less severely damaged ships. After a memorial service on 11 May for her deadcrewmen and the removal of some armament, Shea was underway on 15 May to join convoy OKU #4 (TU 51.29.9), heading for Ulithi Atoll.

Shea got underway from Ulithi on 27 May 1945 and, after a three-day layover at Pearl Harbor, departed for Philadelphia on 9 June. She arrived at the Philadelphia Navy Yard on 2 July, visiting San Diego and transiting the Panama Canal en route. Shea underwent extensive repairs and post-repair trials before leaving Philadelphia on 11 October for shakedown at Casco Bay, Maine. While in the area, Shea celebrated her first peacetime Navy Day at Bath, Maine.

From 1946 to late 1953, Shea was engaged in normal operations with the Atlantic Fleet. Assigned to MinDiv 2 and based at Charleston, South Carolina, she ranged the Atlantic seaboard and Caribbean Sea. This employment was interrupted late in 1950 by a Mediterranean cruise, during which she visited Trieste on a liaison mission with the British forces in the area. Shea returned to Charleston and the Atlantic Fleet on 1 February 1951 and remained so engaged until September 1953 when she reentered the Pacific.

Shea spent the remainder of her active service in the Pacific, based at Long Beach, California. She participated in numerous minelaying and antisubmarine exercises off the West Coast, covering the area from Mexico north to British Columbia and west to Hawaii. In the spring of 1954, she made her only excursion out of that area when she took part in the atomic tests conducted at Eniwetok Atoll in the Marshall Islands. This was her first and only return to any of her old World War II haunts. She arrived back in Long Beach on 28 May and remained in the area until 9 April 1958 when she was placed out of commission in reserve. Shea continued in this reserve status until 1 September at which time, after being surveyed and deemed not to be up to fleet standards, she was stricken from the Navy list.

Shea earned one battle star for her part in the Okinawa campaign during World War II.