Glenn Andreotta was born on October 30, 1947, in Blairstown, New Jersey. He enlisted in the U.S. Army on May 6, 1965, and completed basic training at Fort Leonard Wood, Missouri, in July 1965. Pvt Andreotta next attended Advanced Individual Training as a Field Radio Repairman at Fort Gordon, Georgia, from July to December 1965, followed by additional training and taking leave before departing for Southeast Asia in March 1966. He served as a Field Radio Repairman with Headquarters Company of the 41st Signal Battalion in South Vietnam from April 1966 to January 1967, and then with Company C of the 41st Signal Battalion in South Vietnam from January 1967 until he returned to the United States in April 1967. SP4 Andreotta served as a Communications Repairman with the U.S. Army Special Forces Training Group Support Element at Fort Bragg, North Carolina, from May 1967 until he departed for Southeast Asia for a second tour in Vietnam in October 1967. His next assignment was as a Field Radio Repairman with Headquarters Company of the 198th Light Infantry Brigade in South Vietnam from November 1967 to February 1968, followed by service as an Infantryman, Helicopter Crew Chief, and Helicopter Door Gunner with Company B (Aero-Scout Company) of the 123rd Aviation Battalion in South Vietnam from February 1968 until he was killed in action in South Vietnam on April 8, 1968. A few weeks before his death, SP4 Andreotta was part of a helicopter crew that heroically attempted to stop the massacre at My Lai, South Vietnam, on March 16, 1968. For his heroism, he was originally awarded a Bronze Star Medal for Valor, and this award was upgraded to the Soldier's Medal in 1998. Glenn Andreotta was buried at Valhalla Cemetery in St. Louis County, Missouri.

The Citation for the Bronze Star Medal for Valor that was upgraded to the Soldier's Medal reads:

For heroism in connection with military operations against a hostile force in the Republic of Vietnam. Specialist Four Andreotta distinguished himself by exceptionally valorous actions on 16 March 1968 while serving with the Aero-Scout Company of the 123d Aviation Battalion. On that date, he was serving as crew chief aboard a helicopter which was flying a reconnaissance mission over the village of My La for Task Force Barker. As the aircraft was passing over the area, Specialist Andreotta observed 15 children hiding in a bunker between ground forces engaged in a heavy fire fight. As the pilot landed the helicopter, Specialist Andreotta unhesitatingly left the aircraft and went to the aid of the children. At that time, an armed helicopter which was flying in support of his aircraft landed nearby and Specialist Andreotta placed the children aboard for evacuation to a secure area. After his aircraft took off, Specialist Andreotta observed a wounded Vietnamese child. Once again the aircraft landed and Specialist Andreotta, without regard for his own safety, left the craft, picked up the wounded child and carried the child to his helicopter. They then flew the child to a hospital for treatment. Specialist Four Andreotta's personal bravery, unselfish concern for the lives of the young children and decisive actions in the face of enemy fire were in keeping with the highest traditions of the military service and reflected great credit upon himself, the Americal Division, and the United States Army.