Kara Zor-El, known as Supergirl, first appeared in Action Comics #252 (May 1959), created by writer Otto Binder and artist Al Plastino. Introduced as Superman's cousin from the doomed planet Krypton, Kara survived Argo City's destruction and arrived on Earth as a teenager, possessing the same powers as her cousin under Earth's yellow sun, including super strength, flight, invulnerability, and heat vision. Initially operating in secret under the identity of orphan Linda Lee, she was adopted by the Danvers family and eventually revealed to the world, serving as Superman's ally while developing her own adventures, including joining the Legion of Super-Heroes.
Supergirl's history includes significant changes across DC reboots. In the pre-Crisis era, she starred in backup features and solo stories, facing villains like Lesla-Lar and exploring her Kryptonian heritage. She heroically sacrificed herself during Crisis on Infinite Earths (1985), dying to save the multiverse and subsequently erased from continuity. Post-Crisis versions introduced alternate Supergirls, such as Matrix (a protoplasmic entity) and Linda Danvers, blending angelic and demonic elements, before Kara Zor-El was reintroduced in Superman/Batman #8 (2004) as a modern take arriving after Superman's establishment.
In recent developments, Supergirl has starred in acclaimed series like Tom King's Supergirl: Woman of Tomorrow (2021–2022), portraying a more hardened, space-faring hero, which inspired the upcoming 2026 film starring Milly Alcock. As of late 2025, an ongoing series by Sophie Campbell launched under DC All In, revisiting her roots in Midvale and confronting classic foes like Lesla-Lar, solidifying her as an independent, optimistic counterpart to Superman while embracing her traumatic past.