He was educated at the royal military academy, and in 1914 he entered the Siamese artillery corps. In 1924–27 he took advanced military training in France, where he became involved with Thai students who were plotting the overthrow of the absolute monarchy. On returning to Bangkok, he served as a major on the army general staff, and in 1928 he received the title by which he was known thereafter, Luang Phibunsongkhram, which he later took as his family name.

After helping organize the bloodless revolution of 1932 (Promoters Revolution), or Promoters Revolution, that forced King Prajadhipok to grant a constitution, Phibunsongkhram rose rapidly in the new, military-dominated government and came to public prominence by suppressing the 1933 rebellion of Prince Boworadet. In 1934 he became minister of defense and worked both to strengthen the army and to popularize military values in the fashion of contemporary Italy and Germany. On becoming premier in December 1938, he worked to mobilize the country (whose name he changed from Siam to Thailand in 1939), espousing ultranationalist and irredentist views. After the fall of France he provoked war (World War II) with French Indochina (1940–41) to regain territories in Laos and Cambodia lost by treaty at the beginning of the century. Already pro-Japanese, when Japan invaded Thailand on Dec. 8, 1941, he quickly concluded an alliance with Japan. He declared war on the United States and Great Britain on Jan. 25, 1942. As field marshal during the war he promoted such modern habits as wearing shoes and hats and exhorted the Thai to follow their “Leader” in a highly authoritarian fashion. Though technically an ally of Japan, Thailand increasingly was treated as an occupied state. A strong, anti-Japanese Free Thai Movement developed, and, when the war began to turn against Japan, Phibunsongkhram's government collapsed (July 1944) and a civilian government took power, controlled from behind the scenes by Pridi Phanomyong.

Postwar civilian governments lacked sufficient public support to maintain public order and economic stability, and they were discredited by the suspicious death of King Ananda Mahidol in 1946. The army seized the government in 1947, and Phibunsongkhram returned as premier in 1948. Almost immediately he commenced efforts to contain the spread of communism in Thailand. He suppressed the economic development of Chinese immigrants in Thailand in an attempt to restrict those who were members of the Chinese Communist Party, and he cooperated with the British-Malay campaigns against communist guerrillas in Thailand-Malaya border areas. During the Korean War he supported UN action by dispatching an expeditionary force of 4,000 troops. In 1954 he further allied Thailand to the West in the Cold War by helping establish the Southeast Asia Treaty Organization (SEATO), with its headquarters in Bangkok. After a brief experiment with democracy in 1956–57, when political parties were allowed and free speech encouraged, he was ousted by military colleagues who had tired of the corruption and inefficiency of his government. He then fled to Tokyo, where he lived until his death.