Korea
Three years later she recommissioned at San Diego, on 5 October 1950, Commander Chester W. Nimitz, Jr. in command, and became the flagship of Destroyer Division 132.
During the Korean War she first joined the TF 77 carrier group in early March 1951. Later that month she joined TF 95. the United Nations Blockading and Escort Force, and participated in the siege of Songin. On 17 July 1951, at Wonsan harbor, shore batteries opened on O'Brien, Blue and Cunningham from three sides in a futile attempt to drive UN vessels from the harbor. The ships went at once into the "War Dance", an evasive maneuver in which ships steamed in an ellipse at 22 knots firing on batteries in each sector as their guns came to bear. This four and a half hour engagement became known as the Battle of the Buzz-saw.
In July and August O'Brien provided covering fire for LSMR bombardment, and coordinated rescue operations which saved three downed Navy pilots and one Air Force pilot. Although both Radio Moscow and Radio Peking reported O'Brien sunk by the North Korean Peoples Army, she returned to San Diego for repairs in late September 1951. On 23 July 1952, she returned to Korea as part of TF 95 and participated in shore bombardment, interdiction and patrol duties near Wonsan Harbor. Ordered to the 7th Fleet with Helena (CA-75), she provided search and rescue protection for carrier aircraft and shore bombardment fire on the east coast of Korea in September. The ship joined Operation "Feint", a mock invasion of Kojo 12–16 October 1952, in which UN forces attempted to lure the enemy into the open. At the end of the month, she left the Korean area for exercises and repairs in Japan before returning to San Diego in mid January 1953.
Read more about this topic: USS O'Brien (DD-725)