As one of the most powerful beings in the DC Universe, Darkseid became a staple Superman villain and a major enemy of the Justice League.

Clark Kent works as a reporter for the Daily Planet. Conveniently, this allows him access to the latest news before the general public.

The character of Clark Kent's boss, Perry White, was created for the radio serial, The Adventures of Superman, and portrayed by actor Julian Noa. The character made his initial appearance in the second episode of the series, which aired February 14, 1940. The character transitioned into the Superman comic book later that year.

When Superman first appeared in comics, Clark Kent, worked for the Cleveland Evening News (Action Comics #2, July, 1938). In Action Comics #7 (Dec. 1938), he had apparently transferred to the Metropolis Daily Star where he worked under editor George Taylor (Superman #2, Fall 1939), an arrangement that remained unchanged through March 1940 (Action Comics #22) when the newspaper suddenly changed to the Daily Planet.

As Superman's friend, Jimmy has special access to the Man of Steel, thanks to Superman's gift to Jimmy of a "signal watch", a wristwatch which, with the press of a button, emits a special ultrasonic frequency signal that Superman can hear anywhere on Earth.

While attending Metropolis University, Clark dated Lori Lemaris, a student who hid her mermaid identity by pretending to be wheelchair-bound and using a blanket to cover the lower half of her body.

Kelex was a Kryptonian robot who originally served Superman's father, Jor-El, on Krypton. Kelex currently maintains Superman's Fortress of Solitude.

Blue Kryptonite has no discernable effect on Kryptonians, but is deadly to Bizarros.

The Legion of Super-Heroes was a team of young superheroes from the 30th and 31st Centuries who were formed with Superman as their inspiration. In his youth, Superman frequently traveled to the future to serve as a member of the Legion as Superboy.

Kirk Alyn played Superman in the 1948 live-action movie serial Superman and its 1950 sequel Atom Man vs. Superman. He later appeared as Lois Lane's father in the 1978 Superman film.