In July 1954, Pate was appointed assistant commandant of the Marine Corps and chief of staff, serving in that capacity with the rank of lieutenant general for eighteen months. On January 1, 1956, he was promoted to the rank of general and executed the oath of office as Commandant of the Marine Corps, succeeding General Lemuel C. Shepherd. Following four years as commandant, he retired with the rank of general. At his retirement ceremonies, December 31, 1959, Pate was awarded the Navy Distinguished Service Medal for "exceptionally meritorious service to the Government of the United States in a duty of great responsibility as Commandant of the Marine Corps from January 1, 1956 to December 31, 1959."