She has had leading roles in films such as the sci-fi action-horror film Priest (2011), the psychological action-thriller Abduction (2011) and the fantasy Mirror Mirror (2012) in the role of Snow White. In 2013, she received wider recognition after taking on the role of Clary Fray in the fantasy The Mortal Instruments: City of Bones, for which she was nominated for the Teen Choice Award for Choice Movie Actress – Action and an MTV Movie Award. She is also known for her roles in independent films, such as the romantic comedy-drama Stuck in Love (2012), the romantic comedy The English Teacher (2013), and the romantic comedy-drama Love, Rosie (2014). In 2016, she won the New Hollywood Film Award and was nominated for a Golden Globe Award for Best Actress – Motion Picture Musical or Comedy for her role as Marla Mabrey in Rules Don't Apply. In 2017, her performance as a young adult with anorexia in the Netflix drama To the Bone was praised, with Collins herself having overcome an eating disorder in the years before the film, and she and director Marti Noxon were honored at Project Heal for the film. She starred as Fantine in the BBC miniseries adaptation of Les Misérables (2018–2019), and in 2019 appeared in two biographical films, as serial killer Ted Bundy's girlfriend Liz Kendall in the Netflix drama Extremely Wicked, Shockingly Evil and Vile, and as J. R. R. Tolkien's wife Edith in Tolkien. Also, she starred in the Netflix series Emily in Paris, which was released on 2 October 2020.