The character first appeared in a Supergirl comic published in 1983, and will take on Melissa Benoist's heroine in the new CBS TV series, reported Digital Spy.
Able to harness harmful radiation, recent comics have also seen Reactron equipped with a heart made of gold Kryptonite - able to render a Kryptonian powerless for 15 seconds.
In some versions of DC canon, Reactron is also responsible for the deaths of Kara's parents - making him one of the Maid of Might's greatest enemies.
He will make his live-action debut in the third episode of Supergirl - the series will premiere October 26 on CBS.