Field Marshal Sarith Thanarath staged a coup in 1957 and served as Thailand's dictator until his death in 1963.

In October 1958 he declared martial law, silencing the experiments in open politics since 1955. Sarith justified his authoritarianism in two ways: he argued for a return to Thai traditions of social order, and he accelerated economic development and social modernisation. His motto was "Nation, Religion, King."

Under Sarith, the monarchy, which had been repressed by Phibul, was revitalized. King Bhumibol Adulyadej (Rama IX) attended public ceremonies, toured the provinces and patronised development projects, becoming a personally revered figure. Sarith introduced to government a new generation of economically liberal technocrats, encouraged private and foreign investment, launched major rural development programs and rapidly expanded educational facilities.

When Sarit died in December 1963 power transferred peacefully to his close associates Generals Thanom Kittikachorn (who became Prime Minister) and Praphas Charusathian (Deputy Prime Minister). Thanom and Praphas basically maintained Sarith's style of government and economic policies, which produced GNP growth rates of over 8 per cent per year during the 1960s.

Staunchly anti-communist, Sarith was an ethnic Lao from Thailand's northeast region. He was a patron of the Lao strongman General Phoumi Nosavan.