As Magic Man, he was banished to Earth by Grob Gob Glob Grod for his crimes against the inhabitants of Mars. Instead of turning his life around as they planned, he acted like a jerk for 200 years. According to Abraham Lincoln, Magic Man could have returned to Mars any time he wanted via the Martian transporter if he had just learned to value other people again, but he instead chose to be a jerk to the people of Ooo. He lives in a filthy house that Finn theorizes represents his chaotic, tormented psyche, where he previously kept a Tiny Manticore in a bottle. In the episode, Magic Man Man holds up a picture with him and Margles together.
Abraham Lincoln mentions that Magic Man used to be "really cool" until the night that he and Margles spent on Olympus Mons, the largest mountain/volcano in the solar system. This event was depicted in Jesse Moynihan's promotional artwork for the episode "Sons of Mars," and later shown in the episode "You Forgot Your Floaties," which shows how that tragedy caused Magic Man's behavior to change dramatically. At one point, Normal Man claims that his transporter (which works by thinking of a loved one) has been broken for 200 years, but seeing as Finn was able to use the Martian transporter by thinking about Jake, it seems Normal Man has neglected to form any emotional attachments since Margles' death. This is confirmed when he is able to use the transporter while thinking about Glob in "Normal Man."
After Grob Gob Glob Grod's apparent destruction in "Astral Plane," Magic Man attempted to steal his residual powers with help from Betty Grof in "You Forgot Your Floaties." While their minds were connected, Betty experienced the origin of Magic Man's madness/jerkiness, but thanks to a mutated Finn and Jake interrupting the process, Betty wound up receiving Magic Man's powers and madness, leaving Magic Man as "Normal Man."
In "Normal Man," he uses Tiny Manticore to retrieve Glob's floating orb-head from orbit, with plans to retrieve the others and send them back to Mars to rule. After Tiny Manticore rebels, Normal Man seeks Finn and Jake's help for rescuing his brother. In the end, Glob realizes that Normal Man has started to recover from his madness and disrupts the transportation process so that he can go back to being in orbit with the other heads, while Normal Man returns to Mars and begins to try to help rebuild the civilization and make amends for being a jerk.