In December 1943, following hospitalization and training in Australia, Lieutenant Colonel Walt led the 2nd Battalion, 5th Marines, in the assault at Cape Gloucester, New Britain, and shortly thereafter was assigned as Regimental Executive Officer. In the middle of this campaign he was ordered to take over command of the 3rd Battalion, 5th Marines, during the intense battle for Aogiri Ridge. During this action, he earned his first Navy Cross and Aogiri Ridge was named "Walt Ridge" in his honor by General Lemuel C. Shepherd, Jr., 1st Marine Division assistant commander. Departing Cape Gloucester in late February 1944, Lieutenant Colonel Walt was ordered to the Naval Hospital, Oakland, California, for treatment of wounds and malaria.