Not be confused with Doctor Chaos of the same name.

Major Story Arcs

Burt Belker was a student of Lana Lang's father, who would accompany him on an archaeology adventure where he would come across the Chaos helmet. Burt presented their findings to Superman's high school class where while showing off, put the helmet on and was possessed by Doctor Chaos. Superman saved Burt soon after. Burt started dating Lana Lang, much to Clark's jealousy. However Doctor Chaos still a had a hold on Burt, making him act weird around Lana, putting her off. Burt stole the helmet back to use it again. He would create an illusion of himself to take Lana out on dates at the same time as Doctor Chaos created chaos across Smallville, although he was eventually found out after trying to murder Lewis Lang. Chaos turned Lana into "Lady Chaos" and kidnapped Clark to a chaos dimension to summon demons to fight him, but Superman would of course put a stop to this, and save Lana.

Doctor Chaos returned in Justice League of America #18 appearing in a single panel in the Chaos realm being killed by a demonic force.

Interestingly, despite appearances, name and powers, at no point did he ever interact or even mention Doctor Fate. Although Burt did mention that it was creation of the lords of chaos, implying it was a means of an avatar for chaos as Doctor Fate is for the lords of order.

Other Versions

Earth-3

Despite Doctor Chaos being a villain already, it is implied that this Doctor Chaos of Earth-3 is just a mirrored version of Doctor Fate, borrowing the name and appearance from the forgotten character.

Injustice 2

Despite not appearing in the game, in the customization for Doctor Fate, you can inverse his color scheme to Doctor Chaos' costume, and this is a direct reference to Doctor Chaos because the costume color is titled "Doctor Chaos."