[6]: 209–210 The rise of Prasat Thong to power was documented in van Vliet's The Historical Account of the war of Succession following the death of King Pra Interajatsia (1650).

When King Songtham died in 1628, Chetthathirat ascended the throne and a great purge of the mandarins who had supported Phra Sisin was instigated, including the Samuha Kalahom or Defence Minister.

Prasat Thong then replaced him as the defence minister with the new title of Okya Suriyawong (Thai: ออกญากลาโหมสุริยวงศ์).

During the King Chetthathirat’s reign, Prasat Thong had Yamada Nagamasa, the head of Japanese mercenaries then known as Okya Senaphimok (Thai: ออกญาเสนาภิมุข), as a supporter.

Prasat Thong sent Okya Kamhaeng and Yamada Nagamasa to lead the Japanese troops to crush the rebels.

As soon as the Japanese mandarin left the city, only about a month after his ascension, the child-king was deposed and subsequently executed.

Prasat Thong had acted as "king-maker" before assuming the throne, by performing the double regicide of King Songtham's sons.

[7]: 55 As a powerful and decisive leader, he promulgated many criminal laws and sometimes, according to Van Vliet, even executed prisoners by himself.

Prasat Thong was interested in controlling the towns in the southern peninsula, perhaps because of profits from overseas trade.

It recounts the major events of the reign including religious constructions, amending the calendar, almsgivings, and festivals.