At some point in his life, the Ruling Counsel of Krypton ordered Zor-El to work with his brother to create the Medusa Virus. Much to Jor-El's dismay, well Zor-El had no qualms about creating the virus. The virus was a fail safe mechanism to protect Krypton, which eradicates all visiting extra-terrestrial life on the planet.
Sending Kara to Earth
When it was determined thath Krypton was facing destruction Zor-El developed a fail safe for Argo City to spare it from the destruction.
Not knowing if the fail safe would have worked Zor-El and his wife Alura decide to sent their daughter Kara to Earth. Before sending her off, Alura told Kara that the trip would be long, but she and her father will be with her in her dreams. Zor-El prepared his daughter's pod and watched as the latter boarded her ship, leaving right before the planet self destructed.
At the end the plan worked and Argo was saved. Zor-El died while trying to use the Harun-El to power the city.
HologramZor-El's intelligence appears as a hologram in the Fortress of Solitude when Kara goes there to learn of Project Medusa. The avatar explains that the virus was created by him as a joint effort between the Military and Science Guilds to kill alien life in the event of an invasion.
This disillusions Kara, as she believed her father was saving lives. In truth, he intended to save only Kryptonian lives, and in so doing had created - albeit unknowingly - the perfect weapon for Cadmus to exploit on Earth. Kara angrily deactivated the AI before he could respond. 
Zor was initially perceived as being very similar to the other Els; compassionate, courageous, and wise. In truth, it seemed he and his brother were quite different; while Jor dismayed at the cruelty of the Medusa Virus, Zor was wholly indifferent to the suffering it would bring. Like all Kryptonians, this cavalier demeanor stemmed from a deeply-ingrained elitist and xenophobic attitude that their civilization had adopted over the millennia; devoted to saving the lives of their own race and kin, but wholly uncaring towards the well-being of other species.
While Kara saw her father as a hero who saved life, after learning more of his true character and the intentions surrounding his work, she - as with her mother - began to see that he was both heavily flawed and not a hero, as he didn't save Krypton and instead worked to end life. However, in the end, this proved to be not completly true as Zor managed to save Argo from destruction, showing thath he genuinely cared for Krypton and tried his best to save his home, or at least a part of it. Despite these flaws, also, Zor-El genuine loved his family and cherished both the well-being of Krypton's citizens and particularly considered the safety and life of his own daughter above all else. In Krypton's final days, it's possible that Zor - like Alura - felt that dying with Krypton was the fate he deserved.
Powers and Abilities
- Kryptonian Physiology: Like all Kryptonians, Zor's genetic structure would have conditioned his body to metabolize the radiation of a younger star - a "yellow" sun - and become charged with overwhelming levels of strength, power, and momentous energy which would have enabled him to develop superpowers.
- Young Starlight Absorption: Had Zor-El been introduced to an environment beneath a younger star than Krypton's Rao - such as Earth's "yellow" sun, Sol - his cells would have metabolized the stronger radiation of the younger star, manifesting themselves in various potent powers parallel to those of Superman.
- Genius-level Intellect: As a preeminent member of both the Science Guild as well as the House of El, Zor-El was widely regarded as one of the most intelligent men on Krypton; possibly even surpassing his brother - the similarly-renowned genius, Jor-El. He was the mind behind developing the Medusa Virus. 
- Bilingual: Zor-El was capable of fluently speaking English and Kryptonese.
Adventures of Supergirl
Behind the scenes
- Zor-El debuted in Action Comics #252 (May, 1959), as the biological father of Kara Zor-El, who also made her debut in the same issue. The latest incarnation of the character becomes the second version of the villain, Cyborg Superman.