In 1957, she made her shakedown cruise through the Caribbean area, ran special trials, and steamed to northern Europe. Early in 1958 the new destroyer again crossed the Atlantic to begin her first Sixth Fleet tour in the Mediterranean Sea. "Decatur" made more such deployments during the late 1950s and early 1960s, as well as serving as a spacecraft recovery ship in September 1961 and taking part in Cuban Quarantine operations in November and December 1962. On 6 May 1964, her superstructure was heavily damaged in a collision with the aircraft carrier "Lake Champlain" (CVS-39). The unrepaired "Decatur" was placed "in commission, in reserve" later in the year to await modernization, and was formally decommissioned on 15 June 1965.