Fan Yanguang
Ren Huan subsequently became a chancellor for Li Siyuan. He also was in charge of the three financial agencies (taxation, treasury, and salt and iron monopolies), and he made Li Song his assistant for salt and iron monopolies. Later, when Li Song's mother died, Li Song left governmental service to observe a mourning period for her. After the mourning period was over, Fan Yanguang, who was then the military governor of Chengde Circuit (成德, headquartered at Zhending), made Li Song his secretary, in charge of the communications. When Fan was later recalled to the imperial government to serve as chief of staff ("Shumishi"), Li Song became a member of the office of chief of staff. While serving there, his title gradually rose from "Shiyi" (), to "Bujue" (補闕, both consultant titles), to imperial chronicler (起居郎, "Qiju Lang"), to a supervisory position at the executive bureau of government (尚書省, "Shangshu Sheng"). Near the end of Li Siyuan's "Changxing" era (930-933), Li Song became an imperial scholar (翰林學士, "Hanlin Xueshi").