Chen Shi was first mentioned in 217 when he participated in the Hanzhong Campaign under Liu Bei's command.
Liu Bei sent him and ten other officers to lead their troops to cut off the enemy's route along the gallery roads at Maminge Path (馬鳴閣道; in present-day Guangyuan, Sichuan).
[3] The second mention of Chen Shi was in 221–222 during the Battle of Xiaoting, which was fought between Liu Bei and his ally-turned-rival, Sun Quan, the founding emperor of the Eastern Wu state.
In the initial stages of the battle, Liu Bei ordered Chen Shi and Wu Ban to lead the Shu navy and station at Yiling (southeast of present-day Yichang, Hubei) in between the east and west banks of the Yangtze River.
Acting on Zhuge Liang's order, Chen Shi led troops to attack Wudu (武都) and Yinping (陰平) commanderies and conquered them for Shu.