Because of the Cold War, the U.S. needed to change its war tactics. As a result, the United States Army created the 5th Special Forces group, 1st Special Forces was created to organize and train guerrillas during Vietnam.
A strong proponent of Special Warfare was President John F. Kennedy. He even went to Fort Bragg's Special Warfare Center to see the training program. He also gave the authorization for the soldier to wear the green berets.
The signature headwear of the Special Forces unit is said to come from the United States' relationship with World War II's British Commandos, who wore a green beret themselves from 1941 on.
SF major and OSS veteran Herbert Brucker designed the green beret two years after the Special Forces formation. According to the Army Special Forces Association's official history, the design was likely created because of the close work between the OSS and the Royal British Commandos.
After it was used by the 1st Lt. Roger Pezelle and his Operational Detachment Alpha team in Germany, at the time, they were not actually sanctioned for use by the Army, but the SF troopers did it anyway.
“The berets were only worn in the field during exercises. The Army would not allow the wearing of berets in garrison.”Retired SF Command Sgt. Maj. Joe Lupyak
Offical Beret Adoption
In the 1960s, President John F. Kennedy decided that the Special Forces were the U.S.'s answer to staying ahead in guerilla wars. It was upon his order that Special Warfare School commander Brig. Gen. William P. Yarborough had his soldiers wear the caps, effectively setting them apart from other Army units.
In 1964, the Green Berets took control over all of the Special Forces in Vietnam. They rallied the indigenous people in Vietnam to fight against the Communists. The 5th SF Group had 84 Civilian Irregular Defense Groups totaling 42,000 men.