Thao was born in 1925. Thao's father was Soạn and his mother was Thanh Nguyễn như. His paternal grandparents were Huyên and Ruẩn Trần. He had three brothers and seven sisters, named Ấp, Thức, Quyên, Đạm, Tiềm, Nhuận, Uông, Tân, Loan and Ty. He was the fourth youngest of the eleven children.