In the year 200X, master robot designer Dr. Thomas Light, and his assistant, Dr. Wily, worked on a project to create human-like robots with advanced intelligence. They created a robot, their first success, which was named Protoman. Protoman was a robot that was humanlike in all ways. With the success of the project, he then builds six more of the Robot Masters to be used for industrial purposes: Cut Man whose first purpose was to cut down trees for loggers, Guts Man whose purpose was to pick up huge rocks for building houses, Ice Man who was meant to be used for arctic exploring, Bomb Man who was meant to open blocked caves, Fire Man who was used to make fuel by burning logs ECT, and Elec Man, to help the price of electricity to drop, and after these robots, Dr, Light made two housecleaning robots, Rock and Roll (the remake has him creating two additional robots: Time Man and Oil Man). The project is a great success, and for his work on it, Light is awarded the Nobel Prize for Physics.

Around this time, Dr. Wily grew envious of Light, and stole the prototype. This robot, named Proto Man (originally called Blues in the Japanese version), was in danger of having his energy generator going critical. Wily gave him a nuclear energy supply to extend his life, and learned much about creating robots from studying his design. (He also likely learned the means to reprogram Light's robots from this.)

Wily snuck into Light's lab one night and reprogrammed the robots, but he failed to reprogram Rock and Roll (who still operated on an earlier system,) and made his getaway. When Light found out that Wily had escaped with the Robot Masters, it was too late, as Wily had already sent his new robotic army out to conquer the city.

Rock, having a strong sense of justice, volunteered to be converted into a fighting robot to stop Dr. Wily and his minions and restore peace to the city.