The original newspaper serials printed in 1939 had Superman's spaceship blowing up upon arriving on Earth, but this was later changed for publicity reasons.

After Superman became a great success on the printed page, publicist Allen "Duke" Ducovny thought that a "Superman Day" in the 1939 New York World's Fair would be a great way to publicize the DC Comics' New York World's Fair Comics. This 100-page special edition was supposed to include the complete story of Superman's origins, which had never been reprinted and collected since Jerry Seigel and Joe Shuster first published them as a newspaper serial. But unknown to most readers, the original comic was edited in order to fit the promotion. Since Kal-El's spacecraft was on display at Superman Day but had exploded in the newspaper strip right after Kal-El came to Earth, Roy Thomas changed the story so that his spaceship survived. As Superman grew and became even more popular, similar changes in the comic book appeared under pressure from the radio show, publicists, and society.

Before the radio show exposed Superman to a wider audience, Superman worked at the Daily Star under editor George Taylor, there was no Jimmy Olsen, no police inspector Bill Henderson, and no kryptonite. Soon enough, Perry White replaced George Taylor, the Daily Star became the Daily Planet, and Jimmy Olsen and Bill Henderson were created. These characters carried on in the comic book, making Superman's world a little bit richer. Even the famous tag line that Superman was "faster than a speeding bullet, more powerful than a steaming locamotive, able to leap tall buildings in a single bound," originiated in the radio show. Before this, Superman had no clearly defined superpowers.

Although the radio show introduced Kryptonite in 1945, the mysterious space rock did not make its first comic appearance until Superman No. 61 in 1949. The glowing rock on Swami Riva's turban is a piece of Kryptonite.

These changes could not have come at a better time. Superman was becoming boring. It seemed like no villain was a match for the Man of Steel. One of the big problems that Superman's early comics faced was his virtual unvulnerability. But when Superman's vulnerability to Kryptonite was introduced in the 1945 radio show as a way for Bud Collyer to take a vacation, the comic writers had a new way to make the Man of Steel a little bit more interesting and human. In fact, kryptonite was not introduced in the comc book until Dec. 1949. Suddenly, Superman's villains had a trump card that they could play and his adventures became more interesting.

Superman was not always the good-hearted hero, as these two early strips show.

The popularity of the Superman radio show brought him into a wider audience of listeners. Originally a children's comic, Superman began to conquer fans of all ages when families would hudde around the radio to listen to the amazing adventures of the Man of Steel. Perhaps catering to this more universal audience, Whitney Ellsworth, who edited Superman from 1941 to 1945, established a code of conduct for Superman, prohibiting him from killing men. Before Ellsworth's guidelines, the Man of Steel was a hardened crime fighter who saw justice in the deaths of evil doers. In one strip, Superman throws a criminal high into the air, and although the panel does not show the man landing, it is implied that he falls to his death.

Early Superman strips did not have the superhero fighting a real super-villain except the occasional story featuring Lex Luthor or Ultra-Humanite. He would fight criminals and save people from corrupt businessmen, for sure, but there was no threat to the American way of life. He saved people from natural disasters and slum lords. Coming out of the Depression era tradition, Superman had no qualms with levelling entire neighborhood in order to have them build decent housing. It was not until the 1946 "Unity House" story line on the radio show did Superman begin fighting for "Truth, Justice, and the American way." In this series of stories, Superman battled religious and racial intolerance instead of mad scientists and crooks. The radio show would even disclose secret Ku Klux Klan code words obtained from the Anti-Defamation League over the air to protest violence and intolerance. The popularity of the "Unity House" series put Superman on the media map, and solidified his image as America's superhero.

Since Superman occupied such a prominent cultural position, it was only natural that he was being used as an educational tool. Teachers encouraged students to read the comic so that they might learn proper grammar and English. In the pages of the comic, the Man of Steel urged children to visit the dentist, advised children how to deal with bullies, and to "eat their egg yolk and stop biting their nails." According to editor Mort Weisinger, "A sugar coating had been found for the pill. " Superman was this nation's first public service announcement. Undoubtedly, the popularity of the radio show played an important role in the globalization of Superman. In a series of adventures in 1946, the Man of Steel battled delinquency and absenteeism. As a result, Newsweek called the Superman radio show the "first children's program to develop a social consciousness."

The Superman radio show took the base that the comic established and added a few personal touches. As a result, it began to influence the comic strip as well. By bringing the Man of Steel to a wider audience, the radio show softened Superman's image so that he was more obviously a do-gooder rather than strong-willed cop. With an audience of captivated children, educators found ways to incorporate Superman into their lesson plans so that learning became more fun. Elements and characters introduced in the radio show were put into the comic, enriching Superman's universe and creating more interesting story lines. Indeed, the radio show globalized Superman, helping him become the American cultural icon that he is today.