Although they were by now selling material to comic-book publishers

The pair re-envisioned the character, who became more of a hero in the mythic tradition, inspired by such characters as Samson and Hercules,[19] who would right the wrongs of Siegel and Shuster's times, fighting for social justice and against tyranny. It was at this stage the costume was introduced, Siegel later recalling that they created a "kind of costume and let's give him a big S on his chest, and a cape, make him as colorful as we can and as distinctive as we can."[7] The design was based in part on the costumes worn by characters in outer space settings published in pulp magazines, as well as comic strips such as Flash Gordon,[20] and also partly suggested by the traditional circus strong-man outfit, which comprised a pair of shorts worn over a contrasting bodysuit.[7][21] However, the cape has been noted as being markedly different from the Victorian tradition. Gary Engle described it as without "precedent in popular culture" in Superman at Fifty: The Persistence of a Legend.[22] The circus performer's shorts-over-tights outfit was soon established as the basis for many future superhero outfits. This third version of the character was given extraordinary abilities, although this time of a physical nature as opposed to the mental abilities of the villainous Superman.[7]

The locale and the hero's civilian names were inspired by the movies, Shuster said in 1983. "Jerry created all the names. We were great movie fans and were inspired a lot by the actors and actresses we saw. As for Clark Kent, he combined the names of Clark Gable and Kent Taylor. And Metropolis, the city in which Superman operated, came from the Fritz Lang film Metropolis, which we both loved".[23]

Although they were by now selling material to comic-book publishers, notably Malcolm Wheeler-Nicholson's National Allied Publishing, the pair attempted to sell their feature as a comic strip. They offered it both to Max Gaines, who passed, and to United Feature Syndicate, which expressed interest initially but rejected the strip in a letter dated February 18, 1937. However, in what historian Les Daniels describes as "an incredibly convoluted turn of events", Gaines ended up selling the concept as the lead feature in Wheeler-Nicholson's new publication, Action Comics. Vin Sullivan, that comic's editor, wrote to Siegel and Shuster requesting that their comic-strip samples be reformatted for the comic-book page, requesting "eight panels a page". However Siegel and Shuster ignored this, utilizing their own experience and ideas to create page layouts, with Siegel also identifying the image used for the cover of Action Comics #1 (June 1938), Superman's first appearance