Dr. Light held a faculty position at an Ivy League University before getting fired for bcontacting dangerous experiments within school grounds. Starved for funds to continue his research, Light turned to crime.
His initial caper occured in a small New York town. At 3 AM, the villain illuminated the skies of the city with enough light to mimic daytime. The policemen and security guards awake and on duty at this time could only stare at this miracle. Meanwhile, the villain burned his way into the armored vault of a local factory. Escaping with the weekly payroll.
He was only noticed by Dr. Mid-Nite/Charles McNider who tracked him down and enganged him in combat. Light gained the upper hand and left the hero defeated and with a twisted ankle. Three nights later, Dr. Light robbed a New York City bank. He used his light to temporarily blind the security guards.
He was again confronted by McNider. Who came prepared this time. He used a "blackout bomb" to cover the both of them in darkness. Without his light and the ability to see, the villain was helpless. He was easily arrested. He resurfaced months later with quite a different plan. He created a life-size replica of the Colosseum, passing it off as a remnant of an ancient civilization. Gullible tourists could visit it ... for a price. McNider arrested him when Dr. Light started selling counterfeit relics to wealthy idiots.
His third plot involved plant control. He used his light to grow plants to enormous sizes and used them as living weapons. A curious side-effect was that people in direct contact with the plants, like Myra Mason, soon exhibited uncontrollable rage and murderous intentions.