Upon the outbreak of the Korean War, Williams was transferred to the staff of 1st Marine Division under Major General Oliver P. Smith in June 1950. He participated in the Inchon landings, Second Battle of Seoul and Battle of Chosin Reservoir. He ran the divisional staff with an iron hand, and was decorated with two awards of the Legion of Merit with "V" Device. He was succeeded by Colonel Victor H. Krulak at the end of January 1951 and transferred back to the United States.