While on its first Mediterranean deployment, it helped to stabilize the Adriatic Sea during the Trieste crisis, and it patrolled the coast of Greece to bolster the country's freedom and national security against threatened Communist domination.

While operating in the eastern Mediterranean during February 1956, it patrolled off Israel and Egypt as the Middle East rumbled over the developing Suez Canal crisis.

Returning to the North Atlantic on 6 June 1959, for further NATO maneuvers, Johnston steamed to Charleston, South Carolina, on 25 July and joined Destroyer Squadron 4 (DesRon 4) for deployment to the Mediterranean.

Departing Charleston on 21 September, it conducted Fleet operations in the western Mediterranean; on 18 December it joined naval units from France, Italy, and Spain along the French coast for a review in honor of President Dwight D. Eisenhower.

Before deploying again to the Mediterranean, Johnston joined in NATO Exercise "Sword Thrust" during the fall of 1960; then it departed Charleston on 8 March 1961, to bolster the 6th Fleet's continuing efforts to maintain peace in the Middle East.

During this brief but important duty its presence did much to stabilize a situation "which had threatened to plunge the country into bitter fighting and a return of the Trujillo dictatorship."

Johnston returned to Charleston on 26 November; and following coastal operations, she steamed to Boston, Massachusetts, where she underwent Fleet Rehabilitation and Modernization (FRAM I) overhaul from 4 January to 31 October 1962.

During this time she received the latest equipment, including ASROC system and QH-50 DASH facilities, to prepare her for new assignment in the modern Navy.

While steaming near Mona Island on 1 February 1963, it rescued sinking Honduran freighter Kirco and towed her to Mayaguez, Puerto Rico.

She returned to Charleston on 7 June, and devoted the rest of the year to operations with Polaris submarines, amphibious exercises, and overhaul to prepare for future service.

There her exercises with this powerful deterrent force helped to stabilize the area while bringing her to peak readiness for any emergency which might threaten the peace.

[2] All 5 inch guns were removed, with 10 box launchers for SM-1 Standard surface to air missiles fitted, four ahead of the bridge and six right aft on the ship's fantail.