Inheriting the post from his father Li Zhengji, he served as the military governor (jiedushi) of Pinglu Circuit (平盧, headquartered in modern Tai'an, Shandong) semi-independently from the imperial government.
He served as a military general in the Chinese Yan rebel state. who later submitted to and became a general of the Tang dynasty, from which Yan had rebelled.
Prior to that, he had already been ruling Weibo Circuit (魏博, headquartered in modern Handan, Hebei) in de facto independence from the Tang imperial government as its military governor (Jiedushi), having succeeded his uncle Tian Chengsi in…