Jor-El was a scientist in Kryptonopolis, on the planet Krypton. He had an identical twin brother, Nim-El and a younger brother, Zor-El. His wife was Lara Lor-Van, who had been Krypton's first astronaut. They had a baby son, Kal-El, who later grew up to become Superman on the planet Earth.
Jor-El discovered that Krypton would shortly be destroyed by an atomic chain reaction. He notified the Science Council and began work on creating rockets to evacuate the population. However, he ran out of time for this project, and only had time to save his baby son. He placed Kal inside a small experimental craft, and programmed it to go to Earth, where Jor-El was aware that his son would develop super-powers.