He was born during the king I of Ratanakosin Era. On the 26th of June, in 1786 he was behind the palace where the Bangkok - noi train station was located. His father was from Rayong province. His mother was from another province. Sunthorn Phu was born after Bangkok city was established. His father and his mother divorced, and then his father became a monk at Bangrum temple. where he was originally from and his mother went to serve princess as a wet nurse. Sunthorn Phu had an opportunity to work in the palace with his mother. Sunthorn Phu felt in love with a lady in the palace. Her name was Jun who was related to the Royal family. They were punished and arrested because their relationship violated the traditional social order. When the king died they were pardoned. Following the pardon, Sunthorn Phu went to visit his father who lived in Rayong province. While he was returning to Rayong he wrote a poem called “Nirat Muang Grang " which became one of his most famous poems . The poem described his journey with great detail. He wrote the poem for his fiancé, Jun. After he returned to the palace in Bangkok he married Jun and they had a son named "Pat" and appointed court poet, before becoming an alcoholic, being left by his wife, and, around 1821, being jailed after a fight. The couple was not married long. After Sunthorn Phu's love affair with another woman, the couple divorced and went their separate ways. This was the first of many marriages ending in divorce. The wife whom he loves the most was Jun.
During Rama II era, the king was very pleased with Sunthorn Phu. The king was so pleased with Sunthorn Phu, in fact, that he was promoted to be Khun Sunthorn Voharn. In King Rama III monanchy, Sunthorn Phu made one detrimental mistake by correcting the king's poem in the presence of the king and King's officers. Sunthorn Phu was stripped of his farmer title as punishment. He entered the Buddhist priesthood but eventually left the priesthood to become a merchant. King Rama IV's princess read his poems called “Phra Apai Manee ". She was very pleased and she asked him to finish the poem. The King Rama IV promoted him to Phra Sunthorn Voharn. He spent the rest of life at peace until he died in 1855. He left behind a legacy of poems that have become famous over time because they describe Thai history. Thai people now study his poems to learn about the history of their country. His poetic works were honored by UNESCO.
He began the epic poem, Phra Aphai Mani in prison, and published it in installments over the next 20 years. The epic tale follows the title character, Prince Aphai Mani, a Byronic hero, in his romantic adventures throughout ancient Thailand.
Sunthorn's nine Nirats, which record his associations between memories and sites he visited, are also popular.