The 3rd Battalion of the 3rd Marine Regiment (3/3) was originally formed at New River, North Carolina in 1942 and saw action on both Bougainville and Guam during World War II, where it won the first of its Presidential Unit Citations for "gallantry, determination, and esprit de corps in accomplishing its mission under extremely difficult and hazardous conditions"; and the first of its Navy Unit Commendations for "outstanding service". Marines in the battalion were awarded one Medal of Honor and seven Navy Crosses during the war. Following World War II, 3rd Battalion was disbanded until 1951, when it was reformed in California. The battalion was alerted for possible deployment during the 1956 Suez War and the 1958 intervention in Lebanon. In 1965, the Marines of 3rd Battalion were deployed to Vietnam and participated in Operation Starlite, the first major Marine engagement of that conflict. The battalion continued to see major action through the Vietnam War and was rotated back to the United States in 1969. Alumni from its time in Vietnam include Sergeant Robert O'Malley the first Marine in Vietnam to be awarded the Medal of Honor, Oliver North, and John Ripley. Around the end of the Vietnam War, 3rd Battalion was deactivated for a second time in 1974.
In 1975, 3rd Battalion was reformed for the third (and last) time at Marine Corps Base Hawaii. During this period, the battalion conducted numerous deployments in the Pacific and Indian Oceans. In 1983, 3rd Battalion deployed off the coast of Lebanon for several weeks during a particularly tense period in the civil war. During the 1980s, the battalion was briefly commanded by Charles Krulak, the 31st Commandant of the Marine Corps, who nicknamed 3rd Battalion 3rd Marines "America's Battalion" because it was similar to the nickname used by the Dallas Cowboys. 3rd Battalion deployed again in 1990 as part of Operation Desert Shield and saw action at the Battle of Khafji and again during the liberation of Kuwait. In the first decade of the 21st century the battalion deployed twice overseas in support of Operation Enduring Freedom in Afghanistan and three times in support of Operation Iraqi Freedom in Iraq.