For the first 16 years of her life, Webb lived in Woodbridge, VA, a town of 50,000, just outside Washington D. C. She is the middle child of 6 with a younger sister, two younger brothers and two older sisters. In 2001 she and several members of her family moved to San Diego, California. Haley enrolled at La Costa Canyon High School.
She dreamed of being a ballerina or a backup dancer and performed in a number of high school productions. She was captain of the dance team and earned a black belt in Tae Kwon Do.
While competing in the 2003 'Talent America Showcase,' she met casting director/manager Gary Shaffer of Upstart Management who was judging the event. He recognized her talent and urged her to move to Los Angeles which she did later that year. Once there, Webb studied with acting legend, Howard Fine.
She also took a master class with JoAnne Baron & D. W. Brown in 2006. A week and a half after finishing the class, she landed her first television role, a guest spot on the CBS legal drama series Close to Home.
She booked her first big movie role in 2009 in the horror/thriller The Final Destination as Janet Cunningham.
She did a number of short films and a few one episode appearances on TV before booking her first recurring role on television in MTV’s Teen Wolf.
In 2012, she made her directorial debut in the short film Patti, about the life and work of musician Patti Smith, in which she played the eponymous role and served as producer, film editor, set decorator, sound editor, and costumer.
As Season 3 progressed, Webb began to receive praise for her portrayal of Jennifer upon her reveal as the Darach.
After her character's death, creator Jeff Davis hinted several times that he wanted to bring her back in some way. In 2017, he gave a reason in an interview when asked if there was a storyline he wanted but never got to do.
"I wanted to do a whole storyline with Derek Hale’s character and the return of Jennifer Blake. I wanted it to be like Vertigo. Part of the idea was that the Darach couldn’t just create a face out of thin air. She had to take one. Derek finds this woman who looks exactly like Jennifer Blake, and sort of like Vertigo, it starts to drive him insane. I always thought that would be a fun idea. If Hoechlin had continued on, that would have been a storyline in Season 5."