Quality Comics
Phantom Lady first appeared in Quality's Police Comics #1 (August 1941), an anthology title the first issue of which also included the debut of characters such as Plastic Man and the Human Bomb. That issue established her alter ego as Sandra Knight, the beautiful Washington D.C, debutante daughter of U.S. Senator Henry Knight. The issue established that it was not her first appearance as the Phantom Lady, but it did not go into her origin. Stories published decades later by DC Comics would give her a proper origin, which was altered several times to give Sandra a more active role. Her skimpy costume was eventually explained as a deliberate tactic to distract her usually male foes.
Sandra Knight assumed the identity of Phantom Lady in a costume consisting of a green cape and the equivalent of a one-piece yellow swimsuit. She used a "black light projector", a device which allowed her to blind her enemies and make herself invisible. She drove a car whose headlights also projected black light when necessary. She was sometimes assisted by her fiance, Donald Borden, an agent of the U.S. State Department.
According to Jess Nevins' Encyclopaedia of Golden Age Superheroes, "she fights the cowgirl Ace of Spades, the arsonist Fire Fiend, the Killer Clown, the Robbing Robot, the woman-killer the Subway Slayer, and the cloud-seeding saboteur the Vulture"
Phantom Lady ran as one of the features in Police Comics through #23. Arthur Peddy continued as the artist through #13, with Joe Kubert drawing her feature in Police Comics #14-16; Frank Borth in #17-21; Peddy again in #22; and Rudy Palais in #23. Phantom Lady also appeared in Feature Comics #69-71 as part of a crossover with Spider Woman and the Raven.
Fox Feature Syndicate & Star Publications
After Quality stopped publishing the adventures of Phantom Lady, what was now simply Iger Studios believed it owned the character and assigned it to Fox Feature Syndicate, a move that would later cause confusion as to who actually owned the character's copyright. The Fox version which premiered in Phantom Lady #13 (taking over the numbering of Wotalife Comics is better known to contemporary comic fans than the Quality version because of the "good girl art" of Matt Baker. Baker altered her costume by changing the colours to red and blue, substantially revealing her cleavage, and adding high-cut loose shorts. Fox published Phantom Lady only through issue 23 (April 1949), though the character guest starred in All-Top Comics #8-17, also with art by Baker. Her rogue's gallery in these two Fox titles included the Avenging Skulls; the Fire Fiend; the Killer Clown; Kurtz, the Robbing Robot; the Subway Slayer and Vulture.
Baker's cover for Phantom Lady #17 (April 1948) was reproduced in Seduction of the Innocent, the 1954 book by Dr. Fredric Wertham denouncing what he saw as the morally corrupting effect of comics on children. The cover, which illustrated Phantom Lady attempting to escape from ropes, was presented by Wertham with a caption that read, "sexual stimulation by combining 'headlights' with the sadist's dream of tying up a woman". In the meantime, Fox went under and its assets were acquired by other publishers, and a Phantom Lady story from All-Top was then reprinted as a backup feature in Jungle Thrills by Star Publications which then itself went out of business.
Ajax-Farrell Publications
Ajax-Farrell Publications then published four issues of the second Phantom Lady title, cover dated Dec. 1954/Jan. 1955 through June 1955. The company also published her as a backup feature in two issues of Wonder Boy.
By then, Wertham's efforts had led to a Congressional investigation into the comics industry, and publishers formed the self-censoring Comics Code Authority in the fall of 1954. Some changes were consequently made to the Phantom Lady's costume, so that her cleavage was covered and shorts replaced her skirt.