He served in this capacity until January 1944, when he was transferred to the Camp Pendleton, California to assume command of newly activated 27th Marine Regiment. Wornham supervised the formation and further training of the regiment and after promotion to colonel in June 1944, he sailed with the 27th Marine Regiment for Hawaii. His unit was subsequently assigned to the 5th Marine Division under Major General Keller E. Rockey and began preparing for the Iwo Jima operation.