Fort Stewart was established in 1940 as an anti-aircraft artillery training center. The post was named after American Revolution hero General Daniel Stewart, veteran of both the War of Independence and the War of 1812. Fort Stewart was surveyed and built in 1940, when war in Europe threatened to draw the US in.


The new post quickly became home for the Anti-Aircraft Artillery Training Center, and named Camp Stewart. Early exercises were with wooden mock-ups of targets, and in some cases guns, as material was in short supply. Once guns, ammunition, and targets were available, live-fire exercises commenced, originally off post, as ranges were not completed. In the fall of 1941 the Army conducted the Carolina Maneuvers, a series of field exercises with about 350,000 troops, including Stewart anti-aircraft units. Overall the maneuvers were a success, giving Army planners much needed insight into the state of readiness. Stewart units, mostly activated National Guard, looked forward to the end of their tour, but were instead some of the first troops ready for deployment when the attack on Pearl Harbor drew the US into World War II.


Suddenly supplies were available, along with new guns, plenty of ammunition, and new range areas. WASP (Women Airforce Service Pilots) fliers were soon available to tow live-fire targets, and shortly Stewart's AA crews were deployed to various overseas theaters. In time the WASP-towed targets were replaced with radio-controlled targets, as industrial aircraft production came up to speed. By 1943, Stewart was also being used as a POW camp for Italian and German soldiers, who were employed as laborers at the fort and on local farms to cover labor shortages.


At the end of the war, the post became a demobilization and separation center, then deactivated, with only two officers, ten enlisted men, and fifty civilian employees. Camp Stewart was used by the Georgia National Guard, but otherwise abandoned.


With the onset of the Korean War, Stewart came back to life, when it was redesignated as the Army's 3rd Artillery Anti-Aircraft Training Center, the post repaired, rebuilt, and upgraded. AA training commence again and units deployed to Korea. In 1956, after the end of the Korean conflict, Camp Stewart was redesignated Fort Stewart, and in 1959 the training center shifted to armor and artillery training, the Army observing that most anti-aircraft was now missile based. In 1961 Fort Stewart was facing a possible closure, with Congressional budget concerns looking at the expected declining need for the post's training. However, quite suddenly, Fort Stewart was one of the most important power projection bases in the Army, as the 1st Armored Division was ordered to post and staged for action as part of the Cuban Missile Crisis. This crisis was defused, however, and Fort Stewart soon after hosted US President John F. Kennedy as he inspected the 1st Armored Division in the after-crisis.


The tense international situation kept Fort Stewart active, as the Vietnam War created a demand for helicopter pilots; now instead of training to shoot down aircraft, Stewart was training to fly. In 1967 the Air Force deactivated nearby Hunter Field, and the Army took possession. The airfield is now part of the Fort Stewart complex, and integral in housing and supplying aircraft and crew for troop transportation overseas.


With the US extraction from Vietnam Fort Stewart's activity level dropped back, once again mainly used by National Guard for two years, until in 1974 the fort gained a Ranger battalion and the 24th Infantry. The fort's large area and integrated air field made excellent training areas, and Fort Stewart has had a stable unit presence since the mid-1970s. In 1996 the 3rd Infantry Division was activated at Fort Stewart, which houses the unit to this day.


In the 1990s and 21st century, Fort Stewart demonstrated its power projection capabilities by sending units to the Gulf War and the Iraq and Afghanistan theaters repeatedly.
Currently, the post is used as a training facility for field artillery, helicopter gunnery, tank, and small arms training, and plays an integral role in the support of assigned, attached and tenant activities and units.