Name: Harleen Quinzel
Alias: Harley Quinn
occupation: Psychiatrist (Formerly), Criminal Henchman, Gang Leader (occasionally)
Home: Gotham City
Education: Doctorate in Psychology from Gotham University
(Warning: this is a more classic interpretation of the character, and doesn’t use any modern sources or interpretations, this is based on the original animated series version and the Arkham Asylum - Arkham Knight versions)
Dr. Harleen Quinzel was a psychiatrist at Arkham Asylum where she met the Joker, though he was very likely manipulating her during their psychological evaluations and therapy sessions Harleen saw something in the Joker, it wasn’t just manipulation, she genuinely fell in love with her patient, the two of them worked together from then on she broke him out and joined him in Gotham as his right hand woman. Their relationship isn’t a model one in the slightest, though contrary to what people assume it’s not as abusive as they say, the Joker doesn’t go out of his way to abuse her, most of the time is on the spot, when he’s suddenly put in a bad mood, though that’s no excuse. however this, combined with her infatuation with him leads to her always running into his arms whenever he calls.
Besides the Joker, Harley has a best friend in Poison Ivy (not a sexual or romantic relationship) who despite her attempts to convince her to leave the joker, Harley still goes back to him. The two of them often go on crime sprees in their spare time, both of them using their talents to work together.
When Harley isn’t with the joker, during situations where she has gotten over him she’s shown interest in Bruce Wayne, and has done the deed with Nightwing (Batman and Harley Quinn animated movie)