According to Kapoor, the name "Kareena" was derived from the book Anna Karenina, which her mother read while she was pregnant with her. Set during the Indo-Pakistani war of 1971, the film centers on a man who illegally transports civilians back and forth across the border.She debuted later that year alongside Abhishek Bachchan in J. Kapoor portrayed Naaz, a Bangladeshi girl who falls in love with Bachchan's character while illegally migrating to Pakistan with her family.

When Kapoor was initially offered the film she refused it, explaining that she would be uncomfortable in the role.

She relented when Mishra approached her for the second time, and in preparation for the role, visited several of Mumbai's red-light districts at night to study the mannerisms of sex workers and the way they dressed.

Rediff.com, however, found her portrayal unconvincing and excessively stereotypical, describing her as "sounding more like a teenager playacting than a brash, hardened streetwalker" and comparing her mannerisms to a caricature.

Kapoor next co-starred in Mani Ratnam's bilingual project Yuva alongside Ajay Devgan, Abhishek Bachchan, Vivek Oberoi, Rani Mukerji and Esha Deol.

Married to actor Saif Ali Khan, with whom she has a son, Kapoor's off-screen life is the subject of widespread coverage in India.

She has a reputation for being outspoken and assertive, and is recognised for her contributions to the film industry through her fashion style and film roles.She went on to receive Filmfare Awards for Best Actress and Best Supporting Actress for her performances in the 2007 romantic comedy Jab We Met and the 2010 drama We Are Family, respectively.Kapoor achieved further success by featuring as the female lead in two of India's top-grossing productions—the 2009 comedy-drama 3 Idiots and the 2015 social drama Bajrangi Bhaijaan—and received praise for her roles in the 2009 thriller Kurbaan and the 2012 drama Heroine.Set against the backdrop of the Mumbai underworld, the film follows the story of an online heist in which her character, Neha Mehra, becomes involved.Although the film was unsuccessful at the box office, Kapoor received positive reviews for her performance, and some critics noted a distinct progression from her earlier roles.Featured opposite Shah Rukh Khan, Kapoor found herself challenged playing the complex personality of her character Kaurwaki (a Kalingan princess) with whom Ashoka falls in love.