In 725, during the reign of Emperor Ruizong's son Emperor Xuanzong, Emperor Xuanzong was set to offer sacrifices to heaven and earth at Mount Tai. Fang Guan drafted a proposed text to accompany his sacrifices, and submitted the text to the chancellor Zhang Shuo. Zhang was impressed and recommended him to be Mishu Lang (秘書郎), a clerk at the Palace Library. He later served as the sheriff of Fengyi County (馮翊, in modern Weinan, Shaanxi). He later left office, but was selected in a subsequent imperial examination seeking to fill county magistrate positions, and was made the magistrate of Lushi County (盧氏, in modern Sanmenxia, Henan). It was said that the people of the county praised his rule. In 734, he was made Jiancha Yushi (監察御史), an imperial censor, but that same year was accused of improper handling of cases and demoted to be the census official at Mu Prefecture (睦州, in modern Hangzhou, Zhejiang). He later successively served as the magistrates of Cixi (慈溪, in modern Ningbo, Zhejiang), Songcheng (宋城, in modern Shangqiu, Henan), and Jiyuan Counties, and was said to rule benevolently and reasonably.