Puller was then made executive officer of the 7th Marine Regiment. While serving in this capacity at the Battle of Cape Gloucester, Puller was awarded his fourth Navy Cross for overall performance of duty between December 26, 1943, and January 19, 1944. During this time, when the battalion commanders of 3rd Battalion, 7th Marines (3/7) and later, 3rd Battalion, 5th Marines (3/5), were under heavy machine gun and mortar fire, he expertly reorganized the battalion and led the successful attack against heavily fortified Japanese defensive positions. He was promoted to colonel effective February 1, 1944, and by the end of the month had been named commander of the 1st Marine Regiment. In September and October 1944, Puller led the 1st Marine Regiment into the protracted battle on Peleliu, one of the bloodiest battles in Marine Corps history, and received his first of two Legion of Merit awards. The 1st Marines under Puller's command lost 1,749 out of approximately 3,000 men, but these losses did not stop Puller from ordering frontal assaults against the well-entrenched enemy. The corps commander had to order the 1st Marine Division commanding general to pull the annihilated 1st Marine Regiment out of the line.