He was said to be ugly in appearance, but knew how to read and write, and eventually became a servant of the powerful eunuch Gao Lishi.
During the Tianbao era (742–756) of Wu Zetian's grandson Emperor Xuanzong, the official Wang Hong (王鉷), who oversaw the imperial stables, was impressed with Li Jingzhong's management of the stables and recommended him to serve on the staff of Emperor Xuanzong's crown prince Li Heng.
Later, when Emperor Suzong, while still fighting Yan forces, moved his headquarters from Lingwu to Fengxiang (鳳翔, in modern Baoji, Shaanxi) in spring 757, he gave Li Huguo a slightly greater title as the head of the crown prince's household (太子詹事, Taizi Zhanshi), and changed his name again to Fuguo (meaning, "one who assists the state").
He also gave Li Fuguo the honorific title of Kaifu Yitong Sansi (開府儀同三司) and created him the Duke of Cheng.
Even criminal cases were ruled on by Li Fuguo, and he was often making orders, in Emperor Suzong's name, reversing officials' decisions.
Even the chancellor Li Kui, who was from a highly honored household, paid him respect as a son or a nephew would, calling him, "Father Five."
Gao Lishi and the general Chen Xuanli (陳玄禮) attended to him, as did Emperor Xuanzong's younger sister Li Chiying (李持盈) the Princess Yuzhen, the lady in waiting Ru Xianyuan (如仙媛), and the eunuchs Wang Cheng'en (王承恩) and Wei Yue (魏悅).
In 761, Li Fuguo was made the minister of defense (兵部尚書, Bingbu Shangshu), but further wanted to be chancellor.
However, as of spring 762, when both Emperors Xuanzong and Suzong were seriously ill, Empress Zhang and Li Fuguo had begun to be rivals.
Li Fuguo gave a major part of the command responsibilities to Cheng Yuanzhen.
In summer 762, at Cheng's secret suggestion, Emperor Daizong issued an edict that stripped Li Fuguo of the titles of minister of defense and assistant of military affairs to the supreme commander—thus stripping him of military command—giving the latter post to Cheng.
Li Fuguo became apprehensive and offered to retire, and Emperor Daizong declined and sent him away with formal respect.
Instead, on November 12, 762,[1] an assassin got into Li Fuguo's mansion and killed him, taking his head and an arm away as well.
Emperor Daizong formally issued an order seeking the arrest of the assassin, and buried Li Fuguo in a grand ceremony, after having a wooden head and wooden arm carved to be buried with the rest of the body, although he gave Li Fuguo the unflattering posthumous name of Chou (醜, meaning "power abuser").