The AAW Modernization removed both of the after 5"/54 gun mounts and installed one AN/SPG-51C Missile Fire Control System (MFCS), one Mk. 13 Guided Missile Launching System (GMLS), one Anti-Submarine Rocket (ASROC) system, and modified the Gun Fire Control System to accommodate an illuminator to provide a second missile capable Gun/Missile Fire Control System (G/MFCS). In term of systems capability, the ship could engage two air targets simultaneously (one with each FCS) using from two to four Tartar medium-range (less than 20 nautical mile range) missiles, depending upon the engagement policy in force (Shoot-Look-Shoot or Shoot-Shoot-Look).
The forward 5"/54 gun mount was retained as were the torpedo tubes. The 5"/54 gun was, nominally, a rapid-fire mount capable of firing over 30 rounds per minute at targets up to ranges of twelve nautical miles. The torpedo launchers each held three Mk 46 torpedos, for use only against submarines,
Parsons was converted in the middle 1960s and was stationed (homeported) in San Diego, California from re-activation until late 1971, when the ship, as part of Destroyer Squadron 15 (DesRon 15), was forward deployed to Yokosuka, Japan. As part of this movement, the families of all elegible crewmen were transported to Japan, where they lived in U.S. Navy Housing, located in both the Yokosuka and Yokohoma areas.
From December of 1971 through December of 1972, Parsons provided support to forces afloat and ashore involved in the Vietnam conflict by operating as:
1 - Naval Gunfire Support (NGFS) unit in both I and IV Corp, with the vast majority of operating time spent very close to the DMZ, supporting Marines in that area.
2 - Search and Rescue (SAR) unit (or escort when a DLG held the SAR position) at both the North (N-SAR) and South (S-SAR) stations in the northern Tonkin Gulf. This station provided a means to rescue downed US pilots.
3 - Carrier escort on Yankee Station.
Parsons left Vietnam for the last time on or around December 19, 1972.
DDG Operations ranged from Anti-Aircraft Warfare (AAW) to Anti-Submarine Warfare (ASW) to Anti-Surface Warfare (SUW) and Naval Gunfire Support (NFGS) and included, as necessary, Electronic Warfare (EW).