The division was reactivated 25 September 1967 at Chu Lai in Vietnam from a combination of units already in Vietnam and newly arrived units. Its precursor, a division-sized task force known as Task Force Oregon was created in Quảng Ngãi and Quảng Tín provinces from the 3rd Brigade of the 25th Infantry Division, the 1st Brigade of the 101st Airborne Division, and the 196th Light Infantry Brigade (all separate brigades that deployed to Vietnam in 1966). Task Force Oregon operated in close cooperation with the 1st Marine Division in the I Corps Military Region. As more US Army units arrived in Vietnam the two divisional brigades were released back to their parent organizations and two arriving separate brigades were assigned to Task Force Oregon, which was in turn re-designated the 23rd Infantry Division (Americal). The division was composed of the 11th, 196th, and 198th Light Infantry Brigades and divisional support units. Both the 11th and 198th brigades were newly formed units.
The Americal, in Vietnam, suffered an important defeat at the Battle of Kham Duc but gave a solid performance during the Tet Offensive, the Battle of Lo Giang and the Battle of Landing Zone Center/Hill 352. Platoon Sergeant Finnis McCleery was awarded the Medal of Honor for his valiant efforts on Hill 352. Sgt. Alan Allen was awarded the Silver Star for this same battle. Both men were members of A Co. 1/6 198th. 20 men from A Company were lost in the Battle of LoGiang on 8 February 1968. A Co. of the 198th was awarded the Presidential Unit Citation for its heroic efforts in the Battle of Lo Giang, 8 February 1968.
The Americal Division became notorious after a platoon of troops from the division led by Lieutenant William Calley slaughtered hundreds of South Vietnamese civilians in the My Lai Massacre in March 1968. A helicopter crew from the division’s 123rd Aviation Battalion, led by Hugh Thompson, Jr., attempted to intervene in the massacre and were later awarded the Soldier’s Medal.] Seymour Hersh broke the story of the massacre in November 1969, and a year later 14 officers – including Samuel W. Koster, the division’s commanding officer – were charged with covering the massacre up. Most of the charges were later dropped, but Koster was subsequently demoted and stripped of his Distinguished Service Medal. For his part, 2nd Lieutenant William Calley was charged, convicted and sentenced to life imprisonment and hard labor on March 31, 1971 for the murder of 22 Vietnamese civilians. President Richard Nixon soon intervened and on April 1, 1971 ordered Calley transferred from Fort Leavenworth to house arrest at Fort Benning, pending his appeal. LT Calley, the only person convicted for the slaughter of hundreds innocent Vietnamese civilians at My Lai, eventually served only three and half years of house arrest and was released in September 1974.
The 198th and 11th Brigades were withdrawn from Vietnam in November 1971, and the division was inactivated. The 196th Brigade was reconstituted as a separate brigade and remained in Vietnam until 29 June 1972, the last major combat unit to be withdrawn. Its 3rd Battalion, 21st infantry (Gimlets) was the last U.S. maneuver battalion to leave Vietnam, on 23 August 1972.
The shoulder sleeve insignia was originally approved for the Americal Division on 20 December 1943. It was redesignated for the 23d Infantry Division on 4 November 1954. On 14 December 1967 the distinctive unit insignia was approved.
The shoulder sleeve insignia’s four white stars on a blue field are symbolic of the Southern Cross under which the organization has served. The blue color stands for infantry.
On the distinctive unit insignia, the blue saltire (cross of St. Andrew) alludes to New Caledonia in the Southwest Pacific where the division was created and first activated on 27 May 1942. Each of the four white stars stands for the Southern Cross constellation on its division insignia, as well as the four World War II campaigns (Guadalcanal, Northern Solomons, Leyte and Southern Philippines) in which the division participated. The anchor refers to the Presidential Unit Citation (Navy) awarded the division for Guadalcanal. The red arrowhead and Philippine sun stand for the assault landing, Southern Philippines, and the award of the Philippine Presidential Unit Citation (7 October 1944 to 4 July 1945). The unsheathed sword with point to top refers to Vietnam where the division was active. In view of the division’s origin and outstanding service in World War II and inasmuch as it was one of the few U.S. Army divisions to bear a name instead of a number, the division’s former name “Americal” has been taken as a motto, the association with that name being both inspirational and of historical military significance.