Commissioned in December 1944, she arrived in the western Pacific war zone in mid-June 1945, in time to participate in the final carrier air raids on the Japanese home islands as part of Task Force 38.

During this combat tour, which lasted into 1951, her missions included support of the Inchon invasion, shelling enemy targets ashore and patrolling the Taiwan Straits.

Via Tsoying Naval Base, Taiwan while underway in the South China Sea on 18 July, Frank Knox ran aground on Pratas Reef, and was only freed after a very difficult salvage effort.

Frank Knox rejoined the active forces in November 1966 and resumed her pattern of nearly all annual Seventh Fleet cruises, frequently taking part in Vietnam combat missions.

Renamed Themistoklis (D210) (from Themistocles Athenian statesman who persuaded Athens to build a navy and then led it to victory over the Persians), she served for another two decades before being placed out of commission in the early 1990s.