Harley Quinn has had a great 32 years in media. I say media because her start didn’t come from DC Comics. It was in Batman: The Animated Series (voiced by the great Arleen Sorkin). She wasn't the first this happened to, but she's the most popular.
Since debuting in Batman’s most popular cartoon, Harleen Quinzel has appeared in various mediums. Here are the most important ones starting with the most influential.
Arleen Sorkin
Arleen Sorkin started it all. In a lot of ways, she *is* Harley Quinn. The “Joker’s Favor” episode of Batman the Animated Series was supposed to be her only episode. Thankfully, it wasn’t. We should all be grateful for Arleen Sorkin's contribution to Batman: The Animated Series. That one episode led to dozens of projects featuring and starring Harley Quinn.
DC Comics (Earth-Prime)
Harley Quinn’s popularity skyrocketed when she premiered in comic books. She eventually ditched Joker, began a positive relationship with Poison Ivy, and tried her best to do better. Like anyone, she’s failed. However, Harley never gave up. She continues to attempt to be someone that she can be proud of. For example, she saved Batman and the world from Poison Ivy’s control (Batman: Everyone Loves Ivy). Not bad for someone who wasn’t supposed to appear after one episode.
Injustice comic books
If you’re looking for a good example of Haley Quinn, the Injustice comic books are the way to go. During this series, writers Tom Taylor and Brian Buccellato constantly reminded readers that Harley was a doctor. Getting a doctorate requires intelligence, focus, and dedication that many people don’t have. They also showed that while she jokes, Harley isn’t one. She was beating people down with and without the strength enhancement pills.
Arkham video games
This version of Harley Quinn was fun. She had all the intensity you want from her with a more adult personality. We saw what she would do in a grimier Gotham City with and without Joker. The latter came with an entertaining DLC during Batman: Arkham Knight.
Harleen Quinzel also appeared in Batman: Arkham Origins. The video above shows how she helped uninformed gamers further understand the beginning of Harley and Joker's relationship in this universe.
Margot Robbie
Margot Robbie helped the popularity of Harley Quinn by bringing her into the world of live-action movies. Suicide Squad wasn’t well received but fans loved her. So much so that she starred in a project (Birds of Prey) despite Suicide Squad failing. We see her again in The Suicide Squad (a sequel by James Gunn). Once again, Margot Robbie shined.
Even if we never see Margot Robbie as Harley Quinn again, she’ll be remembered as a performer who aided in making Harleen popular beyond comics and animated projects. For that, she should be thanked.
Harley Quinn on Max
Harley Quinn is slowly becoming the best adult animated show ever. What Kaley Cuoco has done for the character was exactly what people needed. It’s the first time we’re getting her starring in a role that suits her. She isn’t taking a back seat to Joker or another villain. She’s running the show, staying in love, and becoming a better person. There’s no way anyone could have foreseen Harley Quinn being this good.
Tara Strong
This is me saving the best for last. We should all pay homage to Arleen Sorkin for giving us the voice that created Harley Quinn. She’s a legend. Without her, we don’t get the incomparable Tara Strong. She wouldn’t become the most known voice of Harleen Quinzel and Harley Quinn. Yes, there’s a difference. Harley and Harleen have different tones and speech patterns that show different personalities.
Tara Strong is the voice most people hear when they think of Harley Quinn or read her in the comics. A quick look at her IMDb will show why. She’s voiced her in multiple video games and animated projects. I’m not sure Harley Quinn becomes the icon we see today without Tara Strong.