Kar-Lu was a twelve-year-old boy from Krypton who was distinguished by the fact that he did not wish to receive the customary citizen training as required by all Kryptonians. At fifteen, he became a surveyor and hired a partner named Jan-De. The two embarked on an expedition to the Eiu Sea. During the journey, they came upon a group of criminals set on taking control of the capital city of Kandor. Without citizenship training, Kar-Lu was ill equipped to deal with the threat. Fortunately for him, Jan-De had long since acquired his headband of citizenship and used his skills to save Kar-Lu and himself from their adversaries. After this adventure, Kar-Lu returned to Kandor and applied for citizenship. Years later on Earth, Superman told the tale of Kar-Lu to Jimmy Olsen's cousin Mike in the hopes of convincing him of returning to school.
- This version of Kar-Lu, including all history and corresponding appearances, was initially erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. However the ending of Convergence retroactively prevented that collapse, saving all the alternate realities, though in an "evolved" form. Even though versions of the character may have since appeared, this information does not apply to those versions.
- The era in which Kar-Lu lived is unknown, but he existed in a time period when Kandor was still the capital city of Krypton. Whether Kar-Lu remained in Kandor when it was stolen by Brainiac, or whether he died in the destruction of Krypton is unknown.
- 1 Appearances of Kar-Lu (Earth-One)
- 1 Images featuring Kar-Lu (Earth-One)
- Quotations by or about Kar-Lu (Earth-One)
- Character Gallery: Kar-Lu (Earth-One)