As might have been expected, he did not remain in prison long. He was far too useful to the King. One day, His Majesty had urgent need of his services and so granted him a full pardon. Once again, Sunthorn Phu became the royal favourite, the instructor of royal sons and a general literary adviser. He was one of the famous literary circle, headed by Rama II, that composed one of the finest works in the language, The Story of Khun chang and Khun Phan. He is accredited with having written the chapter about the birth of Phlai Ngarm, son of Khun Phan and the heroine Wan Thong.