One of the main leads of the franchise, Hanna is a formerly overweight girl who becomes a queen-bee after the disappearance of Alison DiLaurentis.
Before Alison DiLaurentis disappears, Hanna is shown as a shy girl with an eating disorder.
She is best friends with Alison DiLaurentis along with Spencer Hastings, Aria Montgomery and Emily Fields.
During the last night of the 7th grade, while having a sleepover in Spencer's sister Melissa's barn, Alison disappeared.
In December 2009, The Futon Critic confirmed the casting of Ashley Benson as Hanna Marin.
He surprises her by knocking on her door, and she apologizes for forgetting and tells him that Alison is inside her home.
She alleges that she would call him after Alison leaves, but she didn't do it, upsetting Travis, who broke up with Hanna the next morning.
[19] However, Hanna calls off her engagement with Jordan in the seventh season, when she finds herself unable to love him the way she wishes she could, hiding the breakup from her friends for a while by wearing a fake diamond ring when she returns to Rosewood.
[20] In the fourth season, Hanna also had a rivalry with Miranda, a girl whom Caleb wanted to help when he decided to move to Ravenswood.
—the Liars—, well as being friend of, Lucas Gottesman, Ezra Fitz, Wren Kingston, Toby Cavanaugh, and Paige McCullers.
Along with her new best friend, Mona Vanderwaal, she rules the school, and they are clearly labelled under the title of “queen bees.” She is dating a popular guy and pastor's son, Sean Ackard.
Shoplifting with Mona gives her a “Bad girl” feel, but when she is caught, her mother realizes that Hanna is doing this to get her father's attention following his leaving the family.
When she is caught by the police, Hanna struggles with the fact that her mother, Ashley, is the main factor of the removal of her charges—Ashley maintained a sexual relationship with Officer Darren Wilden in order to keep clean the image of her family.
In addition, the old group of friends, of which Hanna was a member in the ninth grade, reunites, causing tension between her friendship with Mona.
Her insecurities are not helped when Caleb returns to Rosewood, with secrets of his own, and the pair begin drinking.
Being accepted into her choice of college, Hanna scrambles to collect enough money when her father refuses to pay for her education.
Desperate, and at a loss of other options, Hanna enrolls in a beauty pageant for the cash prize, only to fail miserably.
She, along with the other girls, are being transported to prison when they are abducted and held captive by "A" in a species of house for hostages.
After a collapse, she destroys her bedroom and temporarily breaks up with Caleb; plus, she does not want to be overly protected anymore and decides to find out once and for all who "A" really is.
Afterwards, she graduates and moves to New York City with Caleb, who pays her fee for the NY Fashion Institute of Technology.
She is now engaged to Jordan and Caleb is dating Spencer, thus making Hanna uncertain and confused, since she still has feelings for her former boyfriend.
In season 2, Tabby and Imogen break into Sullivan's office and go through the private practice files, finding some on Hanna, Aria Montgomery, Spencer Hastings, and Emily Fields.