She would get jealous of every girl that he dated/had a crush on.
However, she started dating Zeke in Season 3 and 4. Harper was born in Nemaska backstage behind a nightclub to Marty and Elaine Finkle, a couple of not-so-successful entertainment artists.
Harper's crush on him dies down noticeably, but she still shows jealousy when she meets Juliet Van Heusen.
However, her harshness subsides and she begins to grow kinder toward her.
While Alex doesn't explain the situation or her anger, Harper is given permission to write stories based on their experiences.
Harper briefly speaks with her future self and is given her hat, although she doesn't find out who she is.
This initially upsets Harper, as she's been upstaged by Alex, but Alex tells her that she's earned enough money to move into an apartment and wouldn't want to move out without Harper.
She is one of the three mortals (Zeke, Harper, and Theresa) around the Russos that know that wizards exist.
She previously has an obvious crush on Justin (which was used for comedy on the show) that freaked Justin out.
When the Russo family is preparing itself for a vacation on the Caribbean, Harper was reluctantly dragged into a skirmish in New York subway by Alex, which almost leads to their deaths.
Grounded, Alex later tells Harper that she intends to win the Wizard Competition. In season 3 Harper survives an infestation of monsters in New York, a group of monster hunters trying to arrest her, and helping the Russo with their Halloween party.