From 1838, he spent his remaining years in Tiflis in the Russian Empire, having fled the country due to the schemes of the vizier of Mazandaran, Asadollah Navai.

Born on 29 October 1784, he was from a branch of the Turkoman Bayandur tribe that lived in Bijar, the administrative capital of Garrus.

In the summer of 1829, he was part of the retinue of the Qajar prince Khosrow Mirza, who had been dispatched to Russia to formally apologize for the killing of the Russian diplomat Alexander Griboyedov in Tehran.

Fearing the worst, Fazel Khan escaped by sea to Baku, where he encountered the new Russian viceroy Yevgeny Golovin, and then traveled on to Tiflis with him.

According to the modern historian Marina Alexidze; "It is obvious from these letters that Garrusi was a highly popular and estimated writer among the Iranian intellectuals of his time.

[6] Two works by Fazel Khan has survived; the collection of his letters, which is kept in the Tabriz National Library; the biographical work Tadhkara-ye anjoman-e Khaqan ("The Gathering of Rulers"[6]), which was finished in 1818/19, and has four chapters on the lives of Fath-Ali Shah, the Qajar princes, and panegyrists at Fath-Ali Shah's court along with portions of their poetry.