Debut' Supergirl (movie)
Portrayed by Peter O'Toole
Classification Kryptonian
Affiliation Argoan Council
Abilities Standard Kryptonian

Zaltar was a Kryptonian scientist who lived in the isolated Kryptonian community named Argo City, in a pocket of trans-dimensional space. He showed his favorite student Kara Zor-El to see a unique and immensely powerful item known as the Omegahedron, which he has borrowed without the knowledge of the city government, and which powers the city. However, after a mishap, the Omegahedron is blown out into space. He decides to sentence himself to the Phantom Zone for his mistake. Much to the distress of Zaltar, Kara followed it to Earth in an effort to recover it and save the city.

He stayed in the Phantom Zone for many years in quiet misery, until he met Kara (now called Supergirl), who had been sentenced there by Selena.

Supergirl rallied his help in escaping the Zone, and together the two nearly made it to the top before Zaltar was killed by tidal forces inside the zone.

Thus far, he has only appeared in the movie Supergirl.