John Constantine is a minor character of the animated series Harley Quinn. He is an occult detective and professional sorcerer.
Biography[]
Background[]
John Constantine is an occult detective and professional sorcerer known for doing whatever it takes to get the job done. At some point, Asmodeus gave Constantine a picture of herself, which she signed stating that she loved him. He keeps the picture in his pocket. But it’s unknown if the two are lovers or in a relationship.
Season 3[]
"It's a Swamp Thing"[]
- Main article: It's a Swamp Thing

While at a bar in New Orleans, John Constantine overheard that Poison Ivy was looking for Swamp Thing and offered his services, giving his number to Nora Freeze. He made an offer to Ivy, which required her to outdrink him to tell her where Swamp Thing is located. With the alternative of talking about her feelings like Nora (who says she wishes she had friends like Ivy is to Frank the Plant), Ivy begrudgingly accepts Constantine’s offer. However, Nora ends up out drinking Constantine, Ivy, and Harley Quinn, getting the directions to Swamp Thing's location from Constantine.

The next morning, Constantine was seen sleeping on the bar floor, wearing a shirt reading, "I tanked the shark." While asleep, Harley looked through his pockets, where she found a photo of Asmodeus and a map. She took Constantine's map to find Swamp Thing's location.
Trivia[]
- Matt Ryan previously played John Constantine in the shows that is set in Arrowverse (including his own show Constantine), movies set in DC Animated Movie Universe and the DC Showcase short Constantine: The House of Mystery.
- In the mainline comic universe, John Constantine is the biological father of Tefé Holland, as he was used as a vessel by Swamp Thing to conceive a child with Abby Holland. It has never been mentioned whether he has the same relationship to the show's version of the character.