Nguyễn Văn Nhung was an officer in the Army of the Republic of Vietnam (ARVN). After joining the French Army in 1944 during the colonial era of Vietnam, he soon met and became the aide-de-camp and bodyguard of Dương Văn Minh, and spent the rest of his career in this role as Minh rose up the ranks to become a general. Nhung and Minh later transferred to the French-backed Vietnamese National Army (VNA) during the First Indochina War and he became an officer; the VNA then became the ARVN after the creation of the Republic of Vietnam. A soft-spoken man, Nhung was a professional military assassin best known for his role in the November 1963 coup d'état led by Minh that ousted President Ngô Đình Diệm from office.

Before dawn on January 30, 1964, General Nguyễn Khánh ousted the military junta led by General Dương Văn Minh from the leadership of South Vietnam without firing a shot. It came less than three months after Minh's junta had themselves come to power in a bloody coup against then President Ngô Đình Diệm. The coup was bloodless and took less than a few hours—after power had been seized Minh's aide and bodyguard, Major Nguyễn Văn Nhung was arrested and summarily executed.