Maxwell Dillon was a lineman for the New York Electirc Company. One day he gained super powers when he was struck by lightning while in contact with power lines still connected to their spool. The unusually configured magnetic field generated by the wound spool of cable and live, high-tension wires induced a body-wide mutagenic change to his nervous system. Dillon found himself transformed into a living electrical capacitor.
Taken into S.H.I.E.L.D. custody, Electro was freed by The Crimson Cowl, and invited to join The Masters of Evil in their attack against the Avengers. Confounded in his attack by the sudden appearance of Spider-Man, Electro abandoned the Masters to make his own escape.