Feng Bao was from Shenzhou, a city in northern China's Hebei province. As a child, he attended the Neishutang, a school for eunuchs located within the Forbidden City. There, he received instruction from scholars of the Hanlin Academy. He had a passion for literature, was skilled in playing the flute, and excelled in calligraphy.
In 1538, he began working as a scribe for the Directorate of Ceremonial, a position he held for 15 years. In 1553, he transferred to the seals office, and in 1560, he was appointed deputy director (sili bingbi taijian) of the Directorate of Ceremonial by the Jiajing Emperor. Along with three or four colleagues, he oversaw the compilation and transmission of imperial edicts. In 1567, the newly crowned Longqing Emperor chose him as his personal secretary and also appointed him director of the Eastern Depot, which was responsible for the eunuch secret service and the Imperial Stables. In 1572, shortly before his death, the Longqing Emperor promoted Feng to director (sili changyin taijian) of the Directorate of Ceremonial, making him the highest-ranking eunuch in the Forbidden City. Despite this prestigious position, he continued to oversee the Eastern Depot. At the time, the ten-year-old Wanli Emperor held great respect for three individuals: his mother Empress Dowager Li, Grand Secretary Zhang Juzheng, and Feng, all of whom worked closely together.
Feng was known for his efficiency, capability, and competence. Following the death of Zhang in 1582, he faced criticism from the censors. In early 1583, he was removed from his positions and demoted to a lower-ranking post in Nanjing. Additionally, eight of his closest subordinate eunuchs were also dismissed. His property and that of his relatives were seized. Furthermore, his brother and adopted son, who held high positions in the central military commissions, were imprisoned and ultimately died.
American historian Shih-shan Henry Tsai noted that, despite his love for history and efforts to avoid the mistakes of his predecessors, he ultimately lost his power after sixteen years in office. His downfall was brought about by complaints from fellow eunuchs, who reported to the Emperor that Feng had grown too powerful.
Feng was then replaced as head of the Eastern Depot by Zhang Jing, who held the position until 1590 when he was dismissed due to a loss of the Emperor's confidence.
According to Tsai's monograph on Ming eunuchs, Feng died in 1583 after only a few months in Nanjing. In contrast, Michela Fontana, the Italian biographer of Matteo Ricci in Matteo Ricci: A Jesuit in the Ming Court, and American historian Ronnie Po-Chia Hsia in A Jesuit in the Forbidden City: Matteo Ricci 1553–1610, both state that Ricci met Feng in 1599. At the time, Feng was still one of the most influential figures in Nanjing at the age of seventy.