Dunlap operated along the east coast on training duty and in June 1938 served as an escort at Philadelphia, Pennsylvania for the MS Kungsholm, carrying the Crown Prince of Sweden.

After taking part in the raid on Wake Island on 24 February, she continued to patrol in the Hawaiian area until 22 March, then escorted convoys between various ports on the west coast until returning to Pearl Harbor on 22 October 1942.

In the resulting battle, a night torpedo action, the task group sank three Japanese destroyers and drove the fourth back to its base at Buin, without suffering any damage.

After overhaul at San Diego, California, Dunlap sailed 23 November 1943 for patrol duty out of Adak, Alaska until 16 December when she left for Pearl Harbor, arriving 5 days later.

Dunlap returned to San Francisco 7 July 1944 to join the screen for Baltimore (CA-68) carrying President Franklin D. Roosevelt for conferences and inspections with top Pacific commanders of Pearl Harbor and Alaskan bases.