Superman was created by writer Jerry Siegel and artist Joe Shuster, high school students living in Cleveland, Ohio, in 1933. They sold Superman to Detective Comics, the future DC Comics, in 1938. Superman debuted in Action Comics #1 (cover-dated June 1938).

The origin story of Superman relates that he was born Kal-El on the alien planet Krypton, before being rocketed to Earth as an infant by his scientist father Jor-El, moments before Krypton's destruction.

Discovered and adopted by a Kansas farmer and his wife, the child is raised as Clark Kent and imbued with a strong moral compass. Very early on he started to display various superhuman abilities, which, upon reaching maturity, he resolved to use for the benefit of humanity through a secret "Superman" identity.

In January 1933, Cleveland high school student Jerry Siegel wrote a short story, illustrated by his friend and classmate Joe Shuster, titled "The Reign of the Superman", which Siegel self-published in his fanzine, Science Fiction. The titular character is a vagrant who gains vast psychic powers from an experimental drug and uses them maliciously for profit and amusement, only to lose them and become a vagrant again, ashamed that he will be remembered only as a villain. Siegel's fanzine did not sell well. Siegel and Shuster shifted to making comic strips, which they self-published in a book they called Popular Comics. The pair dreamed of becoming professional authors and believed that syndicated newspaper strips offered more lucrative and stable work than pulp magazines. The art quality standards were also lower, making them more accessible to the inexperienced Shuster.

In early 1933 or in 1934, Siegel developed a new character, also named Superman, but now a heroic character, which Siegel felt would be more marketable. This first prototype of Superman had no fantastic abilities and wore casual clothing.

Humor Publishing was the first the duo approached and showed interest. But before anything could be done, they went out of business.

Siegel believed publishers kept rejecting them because he and Shuster were young and unknown, so he looked for an established artist to replace Shuster. When Siegel told Shuster what he was doing, Shuster reacted by burning their rejected Superman comic, sparing only the cover.

In 1934 Russell Keaton was roped in to redesign Superman: In the distant future, when Earth is on the verge of exploding due to "giant cataclysms", the last surviving man sends his child back in time to the year 1935, where he is adopted by Sam and Molly Kent. The boy exhibits superhuman strength and bulletproof skin, and the Kents teach the child, whom they name Clark, to use his powers for good.

But the newspapers rejected them.

Siegel and Shuster later reconciled and resumed developing Superman. The character became an alien from the planet Krypton with the now-familiar costume: tights with an "S" on the chest, over-shorts, and a cape. They made Clark Kent a journalist who pretends to be timid, and introduced his colleague Lois Lane, who is attracted to the bold and mighty Superman but does not realize he and Kent are the same person.

In 1935, under recommendation, they showed their work to Detective Comics (which had recently bought out National Allied).

Thus, In March 1938, Siegel and Shuster sold all rights to the character to Detective Comics, Inc. for $130 (the equivalent of $2,200 when adjusted for inflation). By this time, they had resigned themselves that Superman would never be a success, and with this deal they would at least see their character finally published.

Shuster based Superman's stance and devil-may-care attitude on that of Douglas Fairbanks, who starred in adventure films such as The Mark of Zorro and Robin Hood. The name of Superman's home city, Metropolis, was taken from the 1927 film of the same name. Popeye cartoons were also an influence. The persona of Clark Kent was inspired by slapstick comedian Harold Lloyd. Kent is a journalist because Siegel often imagined himself becoming one after leaving school. The inclusion of a romantic subplot with Lois Lane was inspired by Siegel's own awkwardness with girls.