Born in Bhambla, a small town in Himachal Pradesh, Ranaut initially aspired to a career in medicine on the insistence of her parents. Adamant on building her own career path, she relocated to Delhi at age sixteen, where she briefly dabbled with modelling. After training under the theatre director Arvind Gaur, Ranaut made her feature film debut with the 2006 thriller Gangster, for which she was awarded the Filmfare Award for Best Female Debut. She subsequently received praise for portraying emotionally intense characters in the dramas Woh Lamhe (2006), Life in a... Metro (2007) and Fashion (2008). For the last of these, she won the National Film Award for Best Supporting Actress and a Filmfare Award in the same category.