High-wire lineman Maxwell Dillon 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, powered by the micro-fine rhythmic muscle contractions that normally regulate body temperature.

Adopting the gaudy garb of a so-called super-villain, the deranged Dillon sought to use his newfound power for personal gain. Electro's first and most frequent nemesis has been the wisecracking, web-slinging super hero known as Spider-Man. He also has battled the blind adventurer Daredevil, the star-spangled Super-Soldier Captain America and the fabled Fantastic Four. Generally, Dillon's criminal actions are governed by a desire for money or revenge.

Hoping to energize his campaign to smear Spider-Man's reputation, Daily Bugle publisher J. Jonah Jameson surreptitiously secured Electro's supercharged services to battle the web-slinger on national television. Before an audience of millions, Spider-Man stood triumphant once more. Electro's extended string of ignominious defeats nearly came to an end when the world-weary villain, hungry for respect, attempted to deprive the entire city of power by drawing it into his body. Dillon almost killing himself as a result, again meeting defeat at the hands of Spider-Man.