2010–13: Breakthrough
In 2010, Rambin appeared as the daughter of Virginia Madsen's and David James Elliott's characters on the ABC television series, Scoundrels. However, the series ended its eight-episode run on August 15, 2010, due to low ratings. Rambin appeared on the Disney Channel show, Wizards of Waverly Place, in the recurring role of Rosie, who is a Guardian Angel turned Angel of Darkness who was in love with Justin to steal the Moral Compass; Rambin made her debut on the episode "Everything Rosie for Justin" and left the show after the episode "Wizards vs. Angels". Later, Rambin was cast in the recurring role of Chloe Hall, on the long-running CW series, One Tree Hill. Then later, Rambin was cast as Molly Sloan on the CBS crime-drama CSI: Miami.
It was announced that Lionsgate and director Gary Ross cast Rambin in her first major studio film, in the role of Glimmer, the cut-throat District 1 Tribute in the first film adaption (2012) of the popular book series called The Hunger Games by Suzanne Collins. In an interview with Seventeen, Rambin explained how she trained for the role, "I did a lot of sword training, which was really challenging. I also did a lot of boxing training and hand-to-hand combat. I just had to get in the mindset of someone who would want to do that every day! It was cool because I pushed myself physically and mentally. I couldn’t be vain about being sweating and smelling gross or worry about taking a hit or two.". After the film's success, Rambin and the cast of The Hunger Games went on a The Hunger Games Convention Tour and also appeared in The World Is Watching: Making the Hunger Games.
Further film roles include Chasing Mavericks (2012), which is based on a real-life story about a surfer called Jay Moriarty. In the film, Rambin played the lead love interest, Kim Moriarty. Rambin later starred in the music video for Green Day's "Stray Heart" which was officially released on November 7, 2012.
Rambin had a lead role in the fantasy film Percy Jackson: Sea of Monsters (2013), playing Clarisse La Rue, a hot-tempered, arrogant, large, and strong demigod (also the lead counselor of the Ares Cabin 5) and Percy's rival throughout the story. In an interview with comingsoon.net, Rambin explained her casting and her time as a brunette, "Yeah, I was really lucky that Thor was able to see me as a brunette with this blonde hair. That's not typically the first thing that comes to mind when you look at me, I don't think. But when I put on that wig – luckily they didn't dye my hair – and change my physicality a lot... Nothing against brunettes – I still felt beautiful. But I felt a lot less inhibited, and I felt down to be a little more brash and powerful and strong. I kind of hid behind all this brown hair, and it gave me the power and confidence to verbally rip this one over here. [Laughs.]" Her portrayal as Clarisse was met with mostly positive reviews. In 2013, Rambin moved to New York City to study acting full-time at the Playhouse West Brooklyn Lab and is now a teacher and staff member at the school.
