Marc Worden, René Auberjonois, Khary Payton, and Kurtwood Smith have voiced the character in animated series and films.

He first appeared in Justice League of America #3 (February 1961) in the story "The Slave Ship of Space", and was created by Gardner Fox and Mike Sekowsky.

In his first appearance, he enslaves the Justice League with his Gamma Gong, and uses them to battle the other three monarchs by threatening to leave all humanity in a paralyzed state.

Kanjar Ro appears in Trinity, having disguised himself as Despero to take his place in a ritual and steal power from Superman, Batman, and Wonder Woman.

As the Green Lanterns take custody of Despero's armada, Ro reveals he has copied Krona's files and will sell them to the highest bidder.

Kanjar Ro is later seen in Oa's prison cells and works with Kyle Rayner to stop a mass breakout in exchange for a reduced sentence.