In the 83 years since her comic book debut, Catwoman has been everything from villain to hero between comics and film. She's most frequently categorized as an anti-hero, someone on a fuzzy moral gray line. While comic books and TV adaptations of Selina Kyle have plenty of space to explore the character's moral scale, on film Selina has always worked best as a villain. This is due to the strength and value of Batman's Rogues Gallery, Selina's own effectiveness as a bad guy, and her own comic book history.
Catwoman first appeared on film in the 1966 Adam West Batman movie. Portrayed by Lee Meriwether, this Catwoman is part of the ensemble villain squad of the film and acts as a femme fatale and decoy damsel to trap the Dark Knight. While the film is more comedic in tone than later Batman films, it's still considered a classic take on the older Silver Age Batman. Catwoman's role in the Villain Squad is a part of what makes it effective. As the Dark Knight's manipulative love interest, she deals him deeper blows than the other villains can.
Why Modern Catwoman Adaptations Always Work Best as Villains
As of this writing, Catwoman's most iconic on-screen outing is still Michelle Pfeiffer's turn in the role in 1992's Batman Returns. While her character in that film has anti-heroic qualities, she overall plays the role of an antagonist, teaming up with the Penguin. She's also a thief who generally opposes the Dark Knight. Anne Hathaway's Catwoman came close to Pfeiffer's, and to many fans her strongest showings in the film are in the first half as a villain -- breaking into Wayne Manor, betraying Batman, and challenging him on his assumptions about Gotham -- rather than the latter half as a guilt-ridden reformed anti-hero. While Zoë Kravitz's turn in The Batman did blend heroism with anti-heroism more than villainy, her role is still structurally antagonistic.
Most of the time when the movies attempt to transform Catwoman into a hero or an ally -- like in 2004's Catwoman and the latter half of Dark Knight Rises -- it has proven unsuccessful. This isn't necessarily a commentary on Selina being "too evil" to be heroic. In fact, plenty of anti-heroes or even villains can make that shift, as Harley Quinn has proven in the comics, TV and film. Rather this speaks to Selina's greater effectiveness as a character when she's presented as an antagonist to Batman on film than as a heroic ally. Changing her into a heroic ally often strips her of her most interesting qualities and the unique challenges she poses to the narrative as a villainous foil. This is in part due, as well, to the Batman films handling Batman's Rogues Gallery better overall than the Bat Family or his allies.
Batman Films Thrive More on Their Villains Than Heroes
Batman's Rogues Gallery is a huge part of the Dark Knight's appeal, perhaps more so than any other superhero in the DC Universe. Every successful Batman film to date has centered the villains. With the sole exception of Batman Begins, the antagonists take center stage in the Dark Knight's movies and drive the story as much as Batman himself, if not more. Batman Forever, Batman and Robin, and The Dark Knight Rises have each attempted to include Robin and sometimes Batgirl, but generally the films do not focus much on Batman's allies. Instead, the focus in a Batman movie tends to be on the Dark Knight Detective chasing down his colorful crew of criminal foils.
Batman's villains are the only comic book Rogues Gallery to have multiple movies centered on them as protagonists. These include Joker, Birds of Prey and the Fantabulous Emancipation of one Harley Quinn, and Catwoman. Because of this, it makes sense that Selina Kyle should continue to occupy her original role as an antagonist rather than as a hero or ally. Whether as a complex femme fatale who toes the line between good and bad, or as a truly villainous love of Bruce's life who uniquely challenges his world views, Catwoman on film succeeds the most when she gets to draw out her claws rather than retreat them.