Jan-De was a young man who lived on Krypton some time prior to the theft of Kandor city. He worked as a surveying assistant to fifteen-year-old Kar-Lu. While mounting an expedition to the Eiu Sea, Jan-De and Kar-Lu were set upon by a group of criminals from Urrika bent on conquering Kandor. When the would-be conquerors trapped Kar-Lu using quicksand missiles, Jan-De was able to free him by using Druasic berries to turn the quicksand solid enough so that Kar-Lu could move. Jan-De's quick thinking saved his friend's life a second time, when he helped to extradite him from the branches of a Whirltop tree. He then created a brush fire to drive the Urrikans back to their vessel, forcing them to abandon their plans of conquest. Jan-De's knowledge and skills inspired Kar-Lu to apply for citizenship training.
- This version of Jan-De (Earth-One), 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.
- 1 Appearances of Jan-De (Earth-One)
- 1 Images featuring Jan-De (Earth-One)
- Quotations by or about Jan-De (Earth-One)
- Character Gallery: Jan-De (Earth-One)