Departing Norfolk, Virginia, early in May 1948 she sailed to the Mediterranean temporarily serving under the United Nations' flag as an evacuation ship off Haifa, Israel, from 24 June through July, during the 1948 Arab-Israeli War.

Meanwhile, to update and increase her value to the Navy, O'Hare was converted during 1953 to a radar picket ship (DDR-889) and in 1958 received installation of the electronic data system.

Steaming from Norfolk, on 1 June 1966, she assumed station as a gun support ship along the coast of Vietnam on 15 July, firing missions in all four Corps areas in the South.

O'Hare served as plane guard for aircraft carriers on "Yankee Station" in the Gulf of Tonkin, participated in "Sea Dragon" operations, patrolled on search and rescue duties off North Vietnam.

In March 1968, along with USS Charles R. Ware from Mayport, O'Hare deployed to the Indian Ocean via Africa and made 17 port calls in the Middle East.