In 214, after the warlord Liu Bei seized control of Yi Province from Liu Zhang, Fei Shi came into the service of Liu Bei. Between 214 and 219, Fei Shi held a number of appointments in Liu Bei's administration, including Administrator (太守) of Zangke Commandery (牂牁郡). Around 219, after Liu Bei declared himself King of Hanzhong, he tasked Fei Shi with travelling to Jing Province to inform Guan Yu about his appointment as General of the Vanguard (前將軍).