An estimated 1,000 children competed in races, rope-skipping contests, and various other events to determine a "Super-Boy" and "Super-Girl" of the day. The celebrity panel of contest judges included famed bodybuilder Charles Atlas and Broadway performer Ray Middleton.

Contest winners William Aronis and Maureen Reynolds were awarded trophies and a meeting with Superman creators Jerry Siegel and Joe Shuster. Semi-finalists were given two complimentary passes to the "Superman Adventure" from Macy's Toyland. Other participants received a "Superman Day" Certificate of Merit.

Both of Superman's creators attended the festivities. As a fan of bodybuilding, Joe Shuster was most excited to have met Charles Atlas. Jerry Siegel and Detective Comics co-founder Jack Liebowitz were filmed together that day. The Kodachrome color footage of the event is from the Siegel estate.

A midday parade was led by the first actor to portray Superman in costume. Photos of the unknown Superman were published in Amazing World of DC Comics #7 (July–August 1975). Editor Allan Asherman asked readers for help identifying the mystery man. Many sources credit contest judge Ray Middleton based on information received by Asherman, but the secret identity remains under debate.

Ray Middleton starred as George Washington and Abraham Lincoln in the World's Fair production of "American Jubilee" from May 11, to October 27, 1940. Milton Braker of The New York Times reported Middleton as a judge, but was unable to identify Superman. Bracker also reported that the Superman actor wore a helmet. Later that afternoon, Middleton was photographed by different sources in front of the "American Jubilee" entrance. According to a 1946 interview with Bud Collyer, the Superman costume was filled by a "brawny, muscle-bound ex-pugilist."

 

The Superman float was accompanied by a procession of Boy Scouts, clowns, and midget autos from the Theme Center to what is now Meadow Lake Bridge in Flushing Meadows Corona Park. During the parade, 10,000 balloons were released containing 150 randomly inserted Superman prize coupons. A trio of trained Asian elephants were provided by "Frank Buck's Jungleland" exotic animal exhibit. DC Comics owner Harry Donenfeld was filmed an elephant.

"Superman Day" was organized by Allen Ducovny and Robert Joffe Maxwell, developers of The Adventures of Superman radio serial. "The Man of Tomorrow" seemed like an obviously choice for the "The World of Tomorrow" theme. The producers sought to attract sponsorships and network syndication for the new program. Ducovny and Maxwell co-wrote the iconic opening: “Faster than an airplane, more powerful than a locomotive, impervious to bullets. ‘Up in the sky – look!’ ‘It’s a bird.’ ‘It’s a plane.’ ‘It’s Superman!’ ”

A transcription disc of the July 3 episode, "Hans Holbein’s Doll Factory" part 5 of 6, was played twice during the day in an event hall. WOR 710 gave away free Superman comic books during the afternoon awards presentation.

The following afternoon, a ticking satchel disguised as a radio was discovered in the British Pavilion. Detectives Ferdinand Socha and Joseph Lynch moved the bag to an area behind the Polish Pavilion. At 5:20 PM, the dynamite inside detonated, killing both officers. A British agent was suspected of planting the bomb to disrupt the July 4 celebration and provoke America into entering World War II. The terrorist act remains unsolved in the New York Police Department open files.

The New York World's Fair permanently closed on October 27, 1940. The first giant Superman balloon appeared in The 17th Annual Macy's Thanksgiving Day Parade on November 21, 1940.

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In high school, Jerry Siegel and Joe Shuster published a one-page preview of the 1933 Chicago World's Fair in their early fan magazine, Science Fiction: The Advance Guard of Future Civilization. "The World Fair '33" was printed in issue No. 4, mailed to subscribers in February 1933. The fanzine includes a fictional review of the RKO feature King Kong. The print run was limited and very few copies still exist.

"Superman at the World's Fair" is featured in the 96-page New York World's Fair Comics (April 1939). The 12-page story was written by Jerry Siegel and illustrated by the Joe Shuster Shop. The team also contributed 12 pages for Slam Bradley, an earlier Siegel and Shuster feature. Superman appears on the cover of New York World's Fair Comics with blonde hair. The cover image was penciled by DC editor Vin Sullivan and inked by Fred Guardineer.

A second issue of New York World's Fair Comics was released in April 1940. The second issue features "Superman at the 1940 World's Fair," written by Jerry Siegel and illustrated by Jack Burnley. Burnley was the first Superman artist hired by DC from outside of the Joe Shuster Shop. Siegel also contributed stories for Slam Bradley and the Red, White, and Blue team.

The cover illustration by Burnley depicts the first appearance of Superman with Batman and Robin. A similar image was later used on advertising materials for the Superman Junior Defense League of America and Superman Victory Kid Club.

In February 1941, DC released a quarterly magazine titled World's Best Comics featuring solo stories for Superman and Batman. The second issue was renamed World's Finest Comics. The series remained in publication for 45 years, ending with issue #323 (January 1986).

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Bracker, Milton. "'Superman' Day is Held." The New York Times, 4 July 1940, p. 13.

Brown, Tweed. "He Makes Like Superman." Tune In, September 1946, pp. 27-29.

Daniels, Les. Superman: The Complete History: The Life and Times of the Man of Steel. Chronicle, 2004.

Hayde, Michael J. Flights of Fantasy: The Unauthorized but True Story of Radio & TV's Adventures of Superman. BearManor Media, 2009. 

"Kids Compete for Superman Awards." World's Fair Daily, no. 54, 3 July 1940, p. 1.

Kobler, John. "Up, Up and Awa-a-y! The Rise of Superman, Inc." The Saturday Evening Post, 21 June 1941, pp. 14-15, 73-76.

Pasko, Martin. The DC Vault: A Museum-in-a-Book Featuring Rare Collectibles from the DC Universe. Running Press, 2008.

"Police Die in Blast - Timed Device Explodes After It Is Taken Out of Pavilion." The New York Times, 5 July 1940.

Ricca, Brad. Super Boys: The Amazing Adventures of Jerry Siegel and Joe Shuster–the Creators of Superman. St. Martin's Griffin, 2014.

Siegel, Jerry. Creation of a Superhero. Draft. 1979.