It is not known when Li Daoguang was born. HIs family was originally from what would become Hua Prefecture, but by Li Daoguang's time had moved to the Tang Dynasty capital Chang'an. The family claimed to be descended from the Han Dynasty general Li Ling, who had surrendered to Xiongnu after being surrounded. According to their claims, an ancestor of theirs and descendant of Li Ling eventually became a subject of Northern Wei and, as he met the Northern Wei emperor at Bing Hall, was given the family name of Bing. Li Daoguang's great-grandfather Bing Ming served as a commandant during Sui Dynasty and was created the Duke of Longju. Li Daoguang's grandfather Bing Can later became a subject of Tang Dynasty, as he was an acquaintance of Tang's founder Emperor Gaozu; Emperor Gaozu created him the Duke of Ying. In order to observenaming taboo for Emperor Gaozu's father Li Bing, Emperor Gaozu had the Bing family's name changed to Li. Li Daoguang's father Li Kuan served as the minister of worship during the reign of Emperor Gaozu's grandson Emperor Gaozong, and carried the title of Duke of Longxi.
During Wu Zetian's reign
During the reign of Emperor Gaozong's wife Wu Zetian, Li Daoguang served as the prefect of Bian Prefecture. During successive Khitan and Eastern Tujue incursions in 696, all of the prefectures south and north of the Yellow River were panicking, but under Li's governance, Bian Prefecture was not disturbed. Later that year, he was recalled to serve as director of palace affairs, and Wu Zetian gave him the designation Tong Fengge Luantai Pingzhangshi, making him a chancellor de facto. He was also created the Marquess of Jincheng. In 697, he was also made the actingsecretary general of the capital prefecture Luo Prefecture. In 698, he was removed from his chancellor position and again made prefect of Bian Prefecture. That was the last reference to Li Daoguang in history, and it is not known when he died, although it is known that he was given posthumous honors. His son Li Yuanhong later served as a chancellor during the reign of Wu Zetian's grandson Emperor Xuanzong.
