Cao Hong was one of Cao Cao's sworn brothers, forming a core group in their youth alongside Cao Ren, Xiahou Dun, and Xiahou Yuan; they fought together in early conflicts. He also belonged to the Blast Gang, a rival faction led by Li Lie that opposed Cao Cao. Cao Hong participated in the battle against Li Lie when Cao Cao achieved a rhetorical victory over the Blast Gang leader.