Little is known about Baron Heinrich Zemo’s past before he became an agent for the Red Skull.
Aligning himself with M.O.D.O.K. and A.I.M., Heinrich attacked S.H.I.E.L.D.’s helicarrier in hopes to take control of the vessel. This led to a confrontation with Earth‘s Captain America, who at the time believed he was from Counter-Earth, which ended with Zemo being captured and taken into S.H.I.E.L.D. custody.
Sometime later Heinrich managed to escape custody and made his way back to Counter-Earth’s Germany. After Franklin Richards returned the Avengers, Fantastic Four, and Bruce Banner to Earth, it left Counter-Earth without any heroes. Heinrich, devised a plan to trick the world into believing Germany was going to lead the way to restoring the chaotic world back to normal, but in reality had planned to rule it instead. To accomplish this goal, Heinrich Zemo gathered a group of mercenaries together called the Thunderbolts, and left his son Helmut Zemo in second-in-command.
Not completely trusting his son, he secretly kept a close eye on him and learned that his son planned on overthrowing him once they had gained control over the worlds economy. However before Helmut could accomplish this goal, during a battle with the Thunderbolts, the Fixer killed Heinrich’s son by frying his brain and transplanting Baron Helmut Zemo’s mind into his body. Earth’s Helmut Zemo then used the Iron Cross armor to kill Heinrich Zemo.