Was Superman really the first superhero?

Superman was the first character to combine superhuman powers, a costume and a secret identity, debuting in Action Comics #1 in June 1938. Costumed heroes without powers, such as The Phantom (1936), came earlier.

Who was the first masked comic-strip hero?

Lee Falk's The Phantom, launched in 1936, is widely credited as the first costumed crime-fighter in comics, though he has no superhuman powers.

How much later did Batman arrive?

Batman debuted in Detective Comics #27, cover-dated May 1939 — eleven months after Superman.

Who created Superman?

Writer Jerry Siegel and artist Joe Shuster, two teenagers from Cleveland, created Superman and sold the character to Detective Comics, Inc.

Who Was the First Superhero? The Real Answer

Ask ten fans who the first superhero was and you will get Superman ten times. That answer is close enough for a pub quiz, but it is not the whole story — masked crime-fighters, costumed adventurers and characters with superhuman strength were all in print before Superman debuted.

What Superman did was combine the pieces: a secret identity, a costume, powers beyond human limits, and a mission. That template is why every character after him looks the way they do.

Superman came first as a superhero — but not as a costumed hero

Superman was created by writer Jerry Siegel and artist Joe Shuster and first appeared in Action Comics #1, cover-dated June 1938. He is the character the entire genre is measured against, and the modern comic-book industry effectively starts with his success.

The costumed-hero idea, though, was already circulating. Lee Falk's The Phantom began as a newspaper comic strip in 1936, two years earlier, and gave readers the skintight suit and the mask — without superpowers.

FactSuperman debuted in Action Comics #1, cover-dated June 1938, created by Jerry Siegel and Joe Shuster.Source: Encyclopaedia Britannica
FactLee Falk's The Phantom launched as a newspaper strip in 1936, predating Superman by two years.Source: Encyclopaedia Britannica

The pulp heroes who set the table

Before comic books took over, pulp magazines and radio serials were doing the work. Characters like Zorro (1919) and the Shadow (radio, 1930s) established the secret identity, the alter ego and the vigilante mission — the DNA superheroes inherited.

Batman, who arrived a year after Superman in Detective Comics #27 (May 1939), is the clearest descendant of that pulp lineage: no powers, a mask, a fortune and a grudge.

FactBatman first appeared in Detective Comics #27, cover-dated May 1939, created by Bob Kane with Bill Finger.Source: Encyclopaedia Britannica

So what is the honest answer?

If "superhero" means superhuman powers plus a costume plus a secret identity used for good, Superman in 1938 is the first. If it just means a costumed crime-fighter, The Phantom in 1936 gets there first. Both statements are defensible; the difference is the definition, not the history.