Cushman was ordered to the South Vietnam in April 1967 and was assigned as the deputy commander, III Marine Amphibious Force (III MAF). Upon assuming duty as commanding general, III MAF, the largest combined combat unit ever led by a Marine, he was promoted to lieutenant general in June 1967. For his service as deputy commander, from April to May 1967, and subsequently as commanding general, III MAF, from June to December 1967, he was awarded the Navy Distinguished Service Medal. A Gold Star in lieu of a second Distinguished Service Medal was awarded for his service as commanding general, III MAF; senior advisor, I Corps Tactical Zone; and I Corps coordinator for United States/Free World Military Forces, from January 1968 to March 1969.
