Zor-El was a member of the House of El, and though he was elder than his brother Jor-El, it was the younger El who was commonly regarded as the patriarch. Although nowhere near as smart as his brother, Zor-El was still a wonderful mind, managing to survive the destruction that befell Krypton.
Despite clearly being knowhere near as smart as his brother, Zor-El and Jor-El were always the best of friends. Zor-El later married Allura and had a daughter, Kara Zor-El and resided in Argo City. Zor began to drift away from his brother when the latter became branded an apocalyptic nut, refusing to help him save Krypton. This began a rivalry between the two, which Zor appeared to always be on the losing end of. After Kandor was attacked by the Collector of Worlds, Zor began to try and reverse engineer Brainiac Technology to discover how the Collector hacked into it. Only on the last second did Zor realize his brother was right about Krypton's fate and much like Jor had done for Kal-El, the Last Son of Krypton, Zor sent Kara towards Earth as well, to raise Kal. Zor attempted to shield Argo City from the explosion, but failed and moments before the city's destruction, his marriage shattered.
Unlike most of the entire population of Krypton, Zor-El, though badly injured, survived the death of Krypton. Picked by Brainiac to be a part of the Colony, Zor had his memory wiped, hair colour changed and was given enhanced robotic powers as he had become a Cyborg sworn to serve the Collector of Worlds. Made the "perfect Kryptonian", Zor-El was sent to travel to other worlds and find other specimens compatible for achieving "perfection". Arriving first on the city of Gularth on the planet Kampar, Zor destroyed nearly the entire city, unable to find any willing to achieve perfection. With this, he decided only he could be perfect.
Zor then travelled to the world I'Noxia where he was met by Supergirl, whom he, due to his memory wipe, was unable to recognize as his own daughter. Determined to gain back his own memories and those of the planet Krypton, when Zor met Supergirl, he had her killed so that her own skin could become his. Upon getting his memories back, he learned not only that Brainiac was coming for him, but that he had killed his own daughter.