Besides Hercules' mythological history and being the protector of Greece, he is shown to have a history with Hulk, always mispronounces Charon's name (which annoys Charon), and causes more problems than he can solve while sporting a big ego. It was stated that the last time Hulk was invited by Hercules, they ended up fighting a Chimera.
The Agents of S.M.A.S.H. travel to Ancient Greece and team up with Hercules to stop Pluto from turning everyone on Earth to stone after he had stolen the Shield of Minerva.