With the outbreak of the Korean War in June 1950, "John A. Bole" began intensive preparations for combat service. Sailing from San Diego on 30 September, she steamed via Japan to join Task Force 77 off the Korean coast. With the amphibious assault on Inchon on 15 September, an end run made possible by control of the sea, the tide of the ground war rapidly reversed. The Communist forces far to the south collapsed. "John A. Bole" shifted from amphibious attack to fire support of advancing UN troops. She then screened carriers during the air operations, helping to support both battle-line air strikes and interdiction of northern supply lines. On 11 April 1951, "John A. Bole" was stationed near the coast of mainland China, three miles off Swatow, China, on the orders of General Douglas MacArthur, in an unsuccessful attempt by him to provoke China into a war with the United States. Armed Chinese junks surrounded the ship, but in the meantime, MacArthur was relieved and the ship was moved away from its "sitting duck" role off the Chinese harbor. "John A. Bole" also steamed with support convoys into Inchon before returning to San Diego in mid-June 1951.