Ge Hong was not a hermit and did not write as one. He belonged to a southern gentry family in Jurong, held military command against a rebellion, was offered and accepted official rank, and applied late in life for a magistracy in the far south specifically because he had heard that cinnabar was available there. The application was granted, he got as far as Guangzhou, and he stayed on Mount Luofu instead.
He is careful about where his knowledge came from, which makes him unusually useful to historians. He names a line of transmission running from Zuo Ci to his own great-uncle Ge Xuan to Zheng Yin, from whom he says he received the alchemical scriptures directly, and he complains that his teacher tested him for years before handing anything over. He lists the titles in the libraries he consulted. Much of what is known about the texts circulating in the south in the third and fourth centuries comes from those lists, and several works survive only as his summaries.
His posthumous career took two directions. Chinese pharmacological and medical literature drew on him steadily, and his Zhouhou beiji fang, a handbook of emergency prescriptions, was mined by later compilers. Meanwhile the Shenxian zhuan gave the growing Daoist religion a gallery of exemplars, and Ge Hong himself was absorbed into it as a transcendent. The man who insisted that transcendence had to be worked for became one of the figures other people worked towards.