Over the years, Superman has met a handful of individuals who have called themselves Supergirl.

The first was from the so-called Pocket Universe. This Supergirl was first discovered by a team of explorers in the Arctic, where she had been buried deep in an ice shelf for apparently several hundred years!

This Supergirl was not a real human being, but rather a protomatter maxrix capable of mimicing any form. She had been designed by the Pocket Universe's Lex Luthor, who modeled her after Clark Kent's childhood sweetheart, Lana Lang.

After she regained consciousness in the Arctic, Supergirl found Superman in Smallville, and persuaded him to come back with her to her own dimension, where he battled the evil General Zod and his companions. Unfortunately, she was gravely wounded in the battle. Superman brought her back to his dimension, and Ma and Pa Kent agreed to look after her while she recovered. Unfortunately, she could not quite adjust to her new life, and took off for deep space on a journey of self-discovery.

While on this journey, she fell into the clutches of Brainiac, who was now in control of Warworld. Brainiac enslaved her and used her as a soldier in his attack on Superman. But Supergirl broke free of his control and, when Brainiac was defeated, decided to return to Earth with Superman.

Her ship crashed on Earth, and was recovered by scientists at Lexcorp. When Lex Luthor II met Supergirl, she was confused and disoriented and thought, at first, that he was her creator, the Lex Luthor from the so-called Pocket Universe. Although that misunderstanding was soon cleared up, Supergirl grew close to Luthor and eventually fell in love with him.

When Superman discovered that Supergirl had joined Team Luthor as Lex's personal bodyguard, he was worried. Supergirl assured him, however, that the secret of his identity was safe.

As Lex Luthor's cloned body began dying, he frantically sought everywhere for a cure, including ordering his scientists to study and dissect Supergirl! Faced with his true nature, the Maid of Might left Luthor's employ.

When Superman was captured and brought to trial before the Tribunal, the Alpha Centurion recruited Superboy, Supergirl, Steel, and the Eradicator to fy to deep space and attempt to rescue the Man of Steel.