Charles was born on the 21st of August, 1946, in Lincoln, Nebraska, to Carl and Alvina and he was the youngest of his three siblings. After graduating from Lincoln Southeast High School, he attended the University of Nebraska-Lincoln but left after one year. When he was drafted into the US Army in 1966, Charles was working in a warehouse and by the 20th of March, 1967, he had been trained as a medic and deployed with the 1st Battalion, 5th Cavalry Regiment, 1st Cavalry Division (Airborne), to the Republic of Vietnam. It was his actions on that day that would earn him the Medal of Honor. The citation reads:

For conspicuous gallantry and intrepidity in action at the risk of his life above and beyond the call of duty. While conducting combat operations against a hostile force, Sp5c. Hagemeister's platoon suddenly came under heavy attack from three sides by an enemy force occupying well-concealed, fortified positions and supported by machine guns and mortars. Seeing two of his comrades seriously wounded in the initial action, Sp5c. Hagemeister, unhesitatingly and with total disregard for his safety, raced through the deadly hail of enemy fire to provide them medical aid. Upon learning that the platoon leader and several other soldiers had been wounded, Sp5c. Hagemeister continued to brave the withering enemy fire and crawled forward to render lifesaving treatment and to offer words of encouragement. Attempting to evacuate the seriously wounded soldiers, Sp5c. Hagemeister was taken under fire at close range by an enemy sniper. Realizing that the lives of his fellow soldiers depended on his actions, Sp5c. Hagemeister seized a rifle from a fallen comrade, killed the sniper, three other enemy soldiers who were attempting to encircle his position, and silenced an enemy machine gun that covered the area with deadly fire. Unable to remove the wounded to a less exposed location and aware of the enemy efforts to isolate his unit, he dashed through the fusillade of fire to secure help from a nearby platoon. Returning with help, he placed men in positions to cover his advance as he moved to evacuate the wounded forward of his location. These efforts successfully completed, he then moved to the other flank and evacuated additional wounded men despite the fact that his every move drew fire from the enemy. Sp5c. Hagemeister's repeated heroic and selfless actions at the risk of his life saved the lives of many of his comrades and inspired their actions in repelling the enemy assault. Sp5c. Hagemeister's indomitable courage was in the highest traditions of the Armed Forces and reflect great credit upon himself.

Charles returned to the states and on the 14th of May, 1968, he traveled to the White House with his mother to receive the Medal of Honor from President Johnson. Johnson had asked Charles during the ceremony how much time in service he had left. Charles told him seventy-two hours, to which Johnson then told a senior officer to change Charles’ mind. Ultimately, he would reenlist and make a career out of the Army. Charles would eventually receive a commission and by the time he retired in June of 1990, he had reached the rank of Lieutenant Colonel after twenty-four years in service.

Charles had married Barbara and they had two children. He went on to serve as an instructor at the Army Command and General Staff College at Fort Leavenworth, Kansas, and he was also a defense contractor that trained soldiers with computer simulations and served on the board of directors of the Congressional Medal of Honor Society. On the 19th of May, 2021, Charles Chris Hagemeister died at the age of 74 at the Saint John Hospital in Leavenworth, Kansas. He is buried in the Leavenworth National Cemetery: Section 69, Row 6, Site 55.