1939–1942 In May 1939, Second Lieutenant Davis completed the Marine Officers'
Basic School at the
Philadelphia Navy Yard, and began a year of service with the Marine detachment on board the in the
Pacific. He returned to shore duty in July 1940 for weapons and artillery instruction at
Quantico, Virginia, and Aberdeen, Maryland. Completing the training in February 1941, he was assigned to the 1st Antiaircraft Machine Gun Battery,
1st Marine Division at
Guantanamo Bay, Cuba. He returned to the United States with the unit in April, and the following month was appointed battery executive officer, serving in that capacity at
Parris Island, South Carolina, and Quantico. He was promoted to first lieutenant in August 1941. That September, he moved with the battery to the Marine Barracks, New River (later
Camp Lejeune), North Carolina. Upon his promotion to captain in February 1942, he was named battery commander.
World War II During World War II, Captain Davis participated in the
Guadalcanal-
Tulagi landings, the capture and defense of Guadalcanal, the Eastern New Guinea and
Cape Gloucester campaigns, and the
Peleliu operation. Beginning in June 1942, he embarked with his unit for the
Pacific area, landing at Guadalcanal two months later. After that campaign, he was appointed executive officer of the 1st Special Weapons Battalion, 1st Marine Division. He was promoted to major on February 28, 1943. In October of that year, he took over command of the battalion and served in that capacity at New Guinea and Cape Gloucester. In April 1944, while on
Cape Gloucester, he was named commanding officer,
1st Battalion, 1st Marine Regiment,
1st Marine Division. Davis' heroism while commanding the 1st Battalion, 1st Marines at
Peleliu in September 1944 earned him the
Navy Cross and the
Purple Heart Medal. During the first hour of the Peleliu landing he was wounded. He refused evacuation, and on one occasion, due to heavy Marine casualties and point-blank Japanese cannon fire, the Japanese broke through, he personally rallied and led his men in fighting to re-establish defensive positions. In October 1944, he returned to
Pavuvu and was promoted to lieutenant colonel.
1944–1950 Returning to the United States in November 1944, he was assigned to Quantico as Tactical Inspector, Marine Corps Schools. He was named Chief of the Infantry Section, Marine Air-Infantry School, Quantico, in May 1945, and served in that post for two years before returning to the Pacific area in July 1947 to serve with the
1st Provisional Marine Brigade on
Guam. He was the 1st Brigade's assistant chief of staff, G-3 (Operations and Training), until August 1948, and from then until May 1949, was assistant chief of staff, G-4 (Logistics). Upon his return from Guam in May 1949, he was named Inspector-Instructor of the 9th Marine Corps Reserve Infantry Battalion in Chicago, Illinois. He served there until August 1950 when he embarked for
South Korea.
Korean War In South Korea, Davis commanded the
1st Battalion 7th Marines, from August to December 1950. During this time one of his men described him as, "...from Georgia and soft spoken. No gruff, no bluff. Never talked down to you and made you feel comfortable in his presence." During the 1st Marine Division's fight to break out of the
Chosin Reservoir area in
North Korea during the
Battle of the Chosin Reservoir on December 1, 1950, Davis led his battalion in and through fierce firefights with the Chinese
People's Volunteer Army from Yudam-ni to Hagru-ri. Davis led in front of his men all the way... marching his battalion at night over mountains in a driving snowstorm, he rescued and saved Fox Company,
2nd Battalion 7th Marines from annihilation at the Toktong Pass. This action also opened the blocked mountain pass to Hagaru-ri allowing two trapped Marine regiments to escape and link up with the rest of the 1st Division at Hagaru-ri. He was recommended for the
Medal of Honor. The medal was presented to Davis by President
Harry S. Truman in a
White House ceremony on November 24, 1952. Davis was also awarded two
Silver Star Medals for gallantry in action, exposing himself to heavy enemy fire while leading and encouraging his men in the face of strong enemy opposition. He received the
Legion of Merit with
Combat "V" for exceptionally meritorious conduct and professional skill in welding the 1st Battalion, 7th Marines into a highly effective combat team. Later, as executive officer of the 7th Marines, from December 1950 to June 1951, he was awarded the
Bronze Star Medal with Combat "V" for his part in rebuilding the 7th Regiment in South Korea after the Chosin Reservoir campaign. He returned to the United States in June 1951 and was assigned to
Headquarters Marine Corps in
Washington, D.C. 1952–1959 Davis served with Headquarters Marine Corps at the
Pentagon until June 1954. He served in the Operations Subsection, G-3, Division of Plans and Policies, until February 1952, when he took charge of the subsection. In April 1953, he became head of the Operations and Training Branch, G-3 Division. While serving in this capacity, he was promoted to full
Colonel in October 1953. The following July, he attended the Special Weapons Employment Course, Fleet Training Center, Norfolk, Virginia, under instruction. In September 1954, he entered the Senior Course, Marine Corps Schools, Quantico. Upon completing the course in June 1955, he served consecutively as assistant director and, later, director, of the Senior School. In October 1957, he was again transferred to Washington, D. C., and served there as Assistant G-2, Headquarters Marine Corps, until August 1959.
1960–1966 In June 1960, Davis completed the course at the
National War College in Washington, D.C. Assigned next to Headquarters,
United States European Command, in
Paris, France, he served from July 1960 through June 1963, as chief, Analysis Branch, J-2, Staff of the Commander in Chief, Europe. On July 1, 1963, he was promoted to
Brigadier general while en route to the United States. Davis' next assignment was in the Far East, where he served as assistant division commander,
3rd Marine Division,
Fleet Marine Force, on
Okinawa, from October 1963 to November 1964. During this period, he also performed additional duty as commanding general,
SEATO Expeditionary Brigade, EXLIGTAS, in the
Philippines, during June 1964; and as commanding general,
9th Marine Expeditionary Brigade, in China Sea Contingency Operations, from August 2, to October 16, 1964. In December 1964, he was assigned to Headquarters Marine Corps. He served as assistant director of personnel until March 1965, then served as assistant chief of staff, G-1, until March 1968. For his service in the latter capacity, he was awarded a second Legion of Merit medal. He was promoted to
Major general in November 1966.
Vietnam War In March 1968, he was sent to the
South Vietnam and served until May 1968 as the Deputy Commanding General of the
Provisional Corps. He then became commanding general, 3rd Marine Division until April 1969. When he took command of the division, he ordered Marine units to move out of their combat bases and engage the enemy. He had noted that the manning of the bases and the defensive posture they had developed was contrary to their normally aggressive style of fighting. As part of this change in tactics, he would order
Operation Dewey Canyon in early 1969 to engage the
People's Army of Vietnam in the
A Shau Valley. During this battle, his son Miles Davis, a rifle company platoon commander in K Company,
3rd Battalion, 9th Marines, was
wounded in action.{{Cite web |url=http://www.1stbattalion9thmarinesfirebase.net/documents/Story%20-%20Operation%20Dewey%20Canyon.pdf
1969–1972 In May 1969, Davis was assigned duty as deputy for education with additional duty as director, Education Center, Marine Corps Development and Education Command, Quantico, Virginia. After his promotion to
Lieutenant general on July 1, 1970, he was reassigned duty as commanding general,
Marine Corps Development and Education Command. On February 23, 1971, President
Richard M. Nixon nominated Davis for appointment to the grade of general and assignment to the position of Assistant Commandant of the Marine Corps. His nomination was confirmed by the
Senate and he received his fourth star on March 12, 1971.
General Davis served as
Assistant Commandant of the Marine Corps until he retired from active duty on March 31, 1972. ==Post-Marine Corps career==