The Green Guardsman, real name Scott Mason, was an alternate-Earth superhero and a member of the Justice Guild of America. Like the rest of his JGA counterparts, the Guardsman was believed to be a fictional character by the residents of the mainstream Earth.

The Green Guardsman wielded a Power Ring very similar to those used by the Green Lantern Corps, with the important exception that his ring was entirely ineffective against aluminum.

Along with his fellow Justice Guild members, the Guardsman sacrificed himself to save his world--twice.