Born in northern Vietnam, Kỳ joined the Vietnamese National Army of the French-backed State of Vietnam and started as an infantry officer before the French sent him off for pilot training. After the French withdrew from Vietnam and the nation was partitioned, Kỳ moved up the ranks of the Republic of Vietnam Air Force to become its leader. In November 1963, Kỳ participated in the coup that deposed president Ngô Đình Diệm and resulted in Diệm's assassination.