He gained prominence in 198 when he killed his superior officer Hao Meng to protect Lu Bu. As a result, Lu Bu gave him control over Hao Meng's troops. He later appeared at the Battle of Xiapi, where he famously battled and injured Xiahou Dun. He disappeared after the battle; it is not known if he deserted or was exiled by Cao Cao.
The novel Romance of the Three Kingdoms contains a famous legend about Cao Xing's fight with Xiahou Dun. He secretly fired an arrow which struck Xiahou Dun in the left eye. Xiahou Dun pulled out the arrow and swallowed the destroyed eyeball, then turned on Cao Xing. Cao Xing was too shocked to move, and was impaled and trampled by Xiahou Dun.
Despite the name, he was not related to Cao Cao.