He hailed from Yangxia 陽夏 (modern Taikang 太康, Henan). In 209, he was dispatched as conscript for the erection of the garrison of Yuyang 漁陽 (modern Miyun 密雲, Beijing), together with Chen Sheng 陳勝. In order to avoid punishment because of delay, Chen Sheng and Wu Guang decided to rebel.
While Chen Sheng took over the lead, Wu Guang was made vice king (jiawang 假王) and marched with his rebel troops towards the west. He conquered the city of Xingyang 滎陽. Shortly later he was killed by his lieutenant general Tian Zang 田臧.