While "Whiteside" completed the return voyage to the west coast, events in the Far East ordained her return to that theater of operations. On 25 June, the armed forces of communist North Korea invaded the Republic of Korea (ROK), and the United States moved rapidly to bolster South Korea. With elements of the 1st Provisional Marine Brigade (Reinforced) embarked, "Whiteside" stood out of San Diego on 14 July, bound for Japan. She made port at Yokosuka on the 30th and, by 2 August, was at Pusan, South Korea, the major port through which United Nations men and materiel were being funneled into the conflict, and landed her marines. She departed Pusan on 5 August and reentered Yokosuka two days later. On the night of 1/2 September, she moved to Kobe and, on the 10th, from there to Inchon carrying troops and supplies to assault Inchon and begin the drive on Seoul. She remained at Inchon from the day of the initial landings, 15 September, until D plus 6 at which time she headed back to Japan. She arrived in Sasebo on the 22nd but departed there again the next day to return to the United States. The attack cargo ship arrived at San Francisco on 8 October and remained there for three weeks before getting underway to return to the Far East. After a non-stop voyage, she arrived in Sasebo on 17 November. On the 23rd, she weighed anchor for Yokosuka where she entered port on the 25th. After a 10-day stay at Yokosuka and a brief stop at Sasebo, "Whiteside" arrived at Inchon on 10 December to participate in the evacuation of United Nations forces on the heels of the massive communist Chinese intervention. The ship returned to Yokosuka on 17 December and headed for home on the 20th. She arrived in San Francisco on 5 January 1951.