Al Simmons was a highly decorated member of the Secret Service (notably saving the President in an attempted assassination) and the CIA. After being murdered in a foreign country by his superior Jason Wynn, Simmons is sent to hell because of his life as an assassin. Making a deal with the devil, Simmons agrees to become a Hellspawn and serve Malebolgia if he is allowed to see his wife, Wanda, one last time. Malebolgia returns Simmons to the living realm, but with only the barest of memory, a badly burned body, and a watch dog, the Clown. Simmons is unaware that five years have passed. His wife has married his best friend, Terry Fitzgerald, and the two have a daughter, Cyan.
His life over, Simmons has two choices before him: follow Malebolgia, or renounce the devil. The two choices come in the form of Clown, a diminutive, portly, disgusting minor demon (who can transform into the huge, fanged, clawed Violator), and Cogliostro (Cog), an apparently homeless old man who knows more about Simmons (whom both call Spawn) and his situation than even he knows.
After many fights involving minions of Heaven and Hell, criminals of Earth, and common street scum, Spawn eventually kills Malebolgia but refuses the throne of Hell. Upon returning to Earth, Spawn discovers he has new powers, but must quickly learn to use them, engaging in battles against Clown, Jason Wynn, and even himself. A new evil named Mammon soon made his presence known, and although he was previously thought to be a background character it has become evident that Mammon is much more important, and more powerful, than anything Spawn has ever faced.