 After a shakedown cruise from 16 March to 1 May, she returned to the San Francisco Naval Shipyard on 15 May 1964; and concluded her post-shakedown on 17 July 1964.During her first years of active service, "Halsey" experimented with a unique system of internal organization combining all the aspects of the weapons systems and CIC under a combat officer; and separate hull and communications administration departments.In 1966, "Halsey" was assigned to Destroyer Squadron 7, Destroyer Division 71, in the Pacific Fleet.