He hailed from Langya 琅琊 (modern Jiaonan 膠南, Shandong) and was a famous literatus in his home town, known for his upright and consequent character. He was therefore employed in the bureau of the Censorate (yushi 御史). During the reign of Emperor Yuan 漢元帝 (r. 49-33 BCE) he was appointed metropolitan commandant (sili xiaowei 司隸校尉), a position he filled with the utmost loyalty and sense of responsibility, so that he was elevated to Grand Master of Splendid Happiness (guanglu dafu 光祿大夫).
Yet a favourite of the emperor, Xu Zhang 許章, intrigued against him, so that he was demoted to commandant of the city gates. When he remonstranted against his degradation and sought the support of Chamberlain for attendants (guanglu xun 光祿勳) Zhou Zhen 周湛 and Zhang Meng 張猛, the new Grand master of splendid happiness, the emperor was so enraged that he demoted Zhuge Feng to a commoner, i. e. he was deprived of the possibility to obtain any state office until the end of his life.