Jerro was an Atlantean from the underwater Atlantean city of Tritonis, where the inhabitants had adapted to undersea life by becoming mer-people. Jerro was an early love interest of Kara Zor-El, better known to the world as Supergirl.
- Asphyxiation: Atlanteans can only exist outside of water for a limited period of time or else they will dehydrate, asphyxiate and ultimately die.
- This version of Jerro (Earth-One), including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 13 Appearances of Jerro (Earth-One)
- 1 Images featuring Jerro (Earth-One)
- Quotations by or about Jerro (Earth-One)
- Character Gallery: Jerro (Earth-One)