In February 1946, following shakedown O'Hare became an active unit of the Navy ready to guard the freedom won during World War II. After spending 1946 in operations ranging from New Brunswick down to the Florida Keys, she embarked her first group of midshipmen for a cruise to Europe during the summer of 1947. Departing Norfolk early in May 1948 she sailed to the Mediterranean temporarily serving under the United Nations' flag as an evacuation ship off Haifa, Palestine, 24 June through July during the first postwar Arab-Israeli conflict. Several goodwill visits took place before departure for home in September at the conclusion of this first deployment with the Sixth Fleet.
Eight additional such tours of duty, prior to the end of 1962, permitted ship's company to gain a great deal of familiarity with the area. Midshipman cruises and NATO maneuvers added new vistas and dimensions to her training exercises as did several rescue operations. Twice in 1952 this destroyer received commendations for her efforts after ships had collided at sea, while in 1957 and again in 1961 aviators from the carriers Randolph and Franklin D. Roosevelt respectively were plucked from the sea. Meanwhile, to update and increase her value to the Navy, O'Hare was converted during 1953 to a radar picket ship (DDR-889) and in 1958 received installation of the electronic data system. The next major modification, in 1963, a FRAM Mk I overhaul, restored her original designation.
The increasing tempo and scope of conflict in Vietnam brought DD-889 an assignment to WestPac duty. Steaming from Norfolk, 1 June 1966, she assumed station as a gun support ship along the coast of Vietnam on 15 July. After firing missions in all four Corps areas in the South and operations off the communist North, O'Hare returned home 17 December via the Suez Canal completing a circumnavigation of the world. She remained along the East Coast until January 1969 when with Squadron 32 she again deployed to the Mediterranean.
Decommissioned October 31 1973, loaned to Spain renamed Méndez Núñez (D63). Stricken June 2 1975. Sold to Spain May 17 1978.
Fate: Stricken and scraped in 1992.
USS O'Hare 1946 before her Fram I mods 
USS O'Hare 1964-1968 after Fram II conversion
