Chen Gong was from Wuyang County (), Dong Commandery, which is located at the border between present-day Henan and Shandong provinces. He joined Cao Cao around 190, at the time when regional warlords around China formed a coalition against Dong Zhuo, a powerful warlord who held Emperor Xian hostage in the imperial capital, Luoyang. Chen Gong's most significant contribution while serving Cao Cao was the taking over of Yan Province (兖州; covering present-day western Shandong) in 193 through diplomatic efforts, a strategic move which laid down the foundation for Cao Cao's subsequent rise in power.