On the newsstand, the cover of Action Comics No. 252 (cover-dated May 1959) looked like a typical Superman issue — until you looked closer. Beside the Man of Steel stood a young girl in the familiar red cape, startled by her own powers. With the story “The Supergirl from Krypton!”, DC Comics introduced a character who turned the Superman mythos into a whole cosmos: Supergirl.
Who is Kara Zor-El?
Created by writer Otto Binder and artist Al Plastino, Supergirl — aka Kara Zor-El — is Superman’s cousin. Her origin ties directly to his: when Krypton was destroyed, part of the city of Argo City survived on a fragment of rock. When disaster threatened there too, Kara’s parents — Zor-El, brother of Superman’s father Jor-El, and his wife Alura — sent their daughter to Earth in a rocket, just as Kal-El once had been.
Under Earth’s yellow sun, Kara has the same powers as her famous cousin. In her first appearance Superman takes her under his wing but keeps her existence secret at first: as “Linda Lee” she grows up in an orphanage in Midvale and trains her powers in secret — his “secret weapon” until the world is ready for a second heroine from Krypton.
Why the debut mattered
Supergirl was no accident. In 1958 DC had already tested audience reaction with a “Super-Girl” try-out character. The response to Kara Zor-El in Action Comics No. 252 was so strong that the “secret weapon” became a fixture: Supergirl got her own series, a permanent place in Superman’s supporting cast, and grew into one of the most important female characters in the entire DC Universe.
That puts No. 252 among the great key issues of the Action Comics series — alongside Superman’s debut in No. 1 (1938) and Brainiac’s first appearance a year earlier in No. 242 (1958). In that era Action Comics was the birthplace of a whole ensemble.
“It’s the Supergirl from Krypton — and she will be my secret weapon until the world is ready to meet her.”
From Silver Age to icon
Supergirl’s path was not unbroken. In the much-discussed storyline “Crisis on Infinite Earths” (1985), Kara died a heroic death and vanished from continuity for years. But her popularity was too great: she returned, was reinvented, and today is a fixture of comics, animation and live-action. The TV series Supergirl (2015–2021) made her familiar to millions.
2026: Supergirl hits the big screen
Here the circle from 1959 to today closes. On June 26, 2026, “Supergirl” arrives as the new DC Studios film — the second movie in the rebooted DC Universe (DCU) after James Gunn’s Superman (2025). Directed by Craig Gillespie, written by Ana Nogueira, and starring Milly Alcock (“House of the Dragon”) as Kara Zor-El.
The plot draws on the acclaimed comic “Supergirl: Woman of Tomorrow” by Tom King and Bilquis Evely: instead of a purely Earthbound hero story, the film follows a cosmic journey across the galaxy. At Kara’s side is the young alien Ruthye, seeking revenge for her father’s death. This Kara is harder and more disillusioned than earlier versions — shaped by years as a teenager watching her homeworld fall before she ever reached Earth.
Striking is how closely the film ties back to the origins: her Kryptonian heritage, the link to Superman (David Corenswet appears as Clark Kent), and her status as a survivor of a lost world — all of it was already seeded in 1959 in Action Comics No. 252. What began as one issue’s “secret weapon” now carries an entire feature film almost seven decades later.
Why looking back is worth it
Anyone who sees the new film is holding the end of a long line that began with a ten-cent comic. Action Comics No. 252 is today a sought-after key issue; high-grade copies fetch five-figure sums at auction. Beyond collector value, the book shows how a single good idea — Superman gets reinforcements from Krypton — created a character who outlasts generations.
The full breadth of Action Comics history and all major milestones from 1938 to today are in our issues overview. And if you want the comic that started the whole saga, see the Action Comics No. 1 reprint.