History
Little is detailed about Johnny's life before Reed Richards became Earth's savior, however it can be presumed that it followed as much of the same path as his Earth-616 counterpart.
Reed Richards implemented successfully his "Solve everything" plan, resulting in a World without diseases, hunger or wars. Doctor Doom travelled back in time to Earth-616, where he tried to prevent this Richards from implementing his plan, stating that it would result in chaos, so he could become the savior of Earth instead of him.
The Fantastic Four followed Doom to Earth-616 and helped him to go to an Earth-83553, where every hero was killed by Hulk, giving him the opportunity to save a Earth.[1]