Born in southern Vietnam, he traveled to France and participated in World War I. Upon his return to French Indochina in 1919, he agitated for greater press freedom and took increased interest in social and political issues. Cao Trieu Phat founded the Worker’s Party (Parti travailliste) in November 1926 and published two newspapers, L’Ère nouvelle then the Nhut Tan Bao. In 1928, he joined the Cao Dai politico-religious sect. Between 1930 and 1945, he was very active in the development of the Cao Dai faith and social activities, especially in his home province of Bac Lieu. On 23 August 1945, following the Japanese defeat, he helped nationalists take over the province before serving as a member of the Committee for National Liberation in Bac Lieu (Uy Ban Giai Phong Dan Toc Tinh Bac Lieu) and as a member of the Provincial Branch of the Viet Minh nationalist front in Bac Lieu (Tinh Bo Mat Tran Viet Minh). He donated land and money to the Viet Minh cause and urged his followers to support the nationalist cause of the Democratic Republic of Vietnam (DRV). In June 1946, the pro-Viet Minh Cao Dai selected him as their deputy to the DRV’s National Assembly. Whereas many of the main Cao Dai leaders would break violently with the southern DRV forces in 1947, Cao Trieu Phat continued to work with the government and sent a telegram of support to Ho Chi Minh in September 1947 to confirm it publicly. Between 1947 and 1954, Cao Trieu Phat served as an advisor to the Resistance and Administrative Committee for Nam Bo and joined the Lien Viet nationalist front. The Indochinese Communist Party inducted him into its ranks in 1948 as he became the main leader of the pro-communist Cao Dai forces. In 1954, following the division of Vietnam into two states during the Geneva Conference, Cao Trieu Phat relocated to northern Vietnam.