The history and origins of the criminal known as Rubberman are largely unrevealed.  He first came to public attention one night in 1948 when he was implicated in a local payroll robbery.  He was witness fleeing the police by Paul Dennis walking his dog, causing Dennis and his pet to switch to their identities as Robotman and Robbie the Robot Dog,  Giving chase, the witnesses Rubberman wrap himself around a lamp post and, as the officers drew near, unwind himself with sufficient force to send the police flying.  As Rubberman tries to escape, Robbie bites his leg but his slung backwards by the elastic properties of Rubberman's leg.  Robotman closes in and belts the criminal but he simply bounces away and over a fence, losing himself in the crowd.

Seeking clues, Robotman decides to visit a local circus and sideshow on the outskirts of town the next day.  There the owner reveals that his India Rubber Man act had left, citing insufficient pay in the circus.  The owner shows Robotman a picture of the act, which is indeed the man from the night before.  The owner suggests Robotman talk to Frank the Fire-Eater who is close with Rubberman but Robotman decides to spy on them disguised as a blind man with a seeing eye dog instead.

That night, Robotman witnesses Rubberman contact Frank surreptitiously.  Frank tells the Rubberman that Robotman had spoken with the owner about him and when the two men witness the blind man, realize he is a spy.  Robotman swiftly ditches the disguise as Frank tries to melt his metal form by breathing fire.  Robotman resists  the flames and douses Frank in water to cancel out his fires.  Rubberman breaks free and slips into a drain pipe too tight for humans to follow but large enough for Robbie to give chase.

As Robbie barks to indicate the course of the pipe, Robotman follows along.  At the end, he finds Rubberman's gang waiting for him and seeing the hero charging at them, the crooks pour liquid rubber onto him, which hardens quickly and ensnares him.  As Rubberman emerges, the ruffians believe they have the upper hand but Robotman begins to remove parts of himself such as fists and feet and fling  them at the crooks with sufficient force to, with Robbie's aid, subdue them until the police arrive (Star-Spangled Comics #77).

The further activities of Rubberman on Earth-Two are not recorded.