He was born in Ayutthaya and given the name Sin. His father Hai-Hong was of Chinese ethnicity, his mother Nok-lang was Thai. When aged 7 he started education in buddhist monastery. After 7 years of education he was sent by his father to serve as a royal page. According to legend when he and his friend Tong-Duang were priests they met a Chinese fortune teller who told them that they both have lucky lines in the palms of their hands and will both become kings. Both did not take it seriously, however Tong-Duang was later the successor of king Taksin, Rama I.
Sin was first deputy-governour and later govenour of the Tak province, which gained him his name Tak-Sin, even though his official noble title was Phya Tak. When he was promoted to be govenour of the Kamphaeng Phet province and had to return to Ayutthaya, the Burmese attacked Ayutthaya. Before the city was sacked in 1767 he escaped with a small army.
After the fall of Ayutthaya the country was split into six parts, with Taksin holding the east coast part. Together with Tong-Duang, now called General Chakri, he managed to drive back the Burmese and reunify the country. On December 28, 1767 he became the new king of Siam, in the new capital Thonburi.
King Taksin had to fight for most of his reign to keep the independence of the country. He sought relief in religion, and eventually he became a fanatic. He was declared insane, and a coup d'état caused him to be removed from his throne. Even though he planned to join the priesthood, he was executed shortly afterward the coup on April 7, 1782.
When the coup started General Chakri was fighting in Cambodia, and he did return quickly. When he arrived in Thonburi the rebels resigned, and Chakri was crowned as king Rama I.
In 1981 the Thai cabinet passed a resolution to give him the honorary title the great. The date of his coronation, December 28, is the official day to homage King Taksin, however not a public holiday.