Her reputation, as they say, precedes her. At Rosewood High, most of the students thought of her as the mean girl archetype: gorgeous, confident, popular, and a total bitch. The way she treated Jenna (Tammin Sursok) when she first showed up as the new girl is a prime example of how she plotted to take potential rivals down.
She could be mean to her own friends. She often mocked Hanna (Ashley Benson) back when Hanna had weight issues. And she almost seemed to enjoy catching Aria’s (Lucy Hale) dad hooking up with a student. She used Emily’s (Shay Mitchell) love for her to manipulate her, keeping her in captivity with her secret.
Her pranks were mean-spirited. Attempting to threaten Jenna with a stink bomb, the dirty trick wound up being a tragic mistake, causing Jenna’s blindness. And her stunt on Halloween, in which she claimed there was someone stalking her in an abandoned house, wound up frightening the Little Liars instead of making them laugh.
She kept big secrets. Not only did Ali keep her friends’ deepest, darkest secrets to herself — she hid her affair with Ian from her friends and everyone else. She convinced the girls to keep “The Jenna Thing” a secret, and she knew that Jason (Drew Van Acker) was related to Spencer (Troian Bellisario) and Melissa (Torrey DeVitto), but didn’t tell anyone.
Sometimes, Ali’s intentions were good when it came to the Little Liars. Even though she instructed Hanna to purge her food (Season 1, Episode 13: “Know Your Frenemies”) to lose weight, it seemed like she just wanted Hanna to lose weight so she could go after the guys she liked (like Sean [Chuck Hittinger], who Alison helped set up with Hanna), and feel better. She never judged Emily for being gay, she encouraged Aria to tell Ella (Holly Marie Combs) what she saw in Byron’s (Chad Lowe) car, and she wanted Spencer to loosen up and stop driving herself crazy with pressure.
Ali was being threatened by “A” too. In “The First Secret,” Ali gets scared and flustered she receives a text from someone while in the costume store. Later in the episode, she gets a package with a voodoo doll and a note, saying “Now it’s my turn to torture you.” At the end of the episode, she received a text from “A” saying, “Dying to find out who I am? You will.”