In 2006, Desai got selected to play the lead role in Ekta Kapoor's television drama Kasamh Se. She was cast as Bani, opposite TV actor Ram Kapoor. The show won her several awards including the Indian Telly Award for Best Actress in a Lead Role.

Desai then entered Jhalak Dikhhla Jaa, the Indian version of BBC Strictly Come Dancing on 7 September 2007 with Choreographer Deepak Singh. Desai impressed the judges every week, but was ultimately eliminated on 10 November 2007 but entered the contest again via wildcard entry on 23 November 2007. Desai then landed a spot in the grand finale of the dance show on 15 December 2007 and won the competition. Desai was awarded the Dancing Star of Jhalak Dikhhla Jaa.

Desai then made a transition to the film industry in 2008. Her first film was Rock On!! (2008), directed by Abhishek Kapoor, where she played the wife of Farhan Akhtar. Desai had to leave Kasamh Se to act in Rock On.

Her next film was Life Partner (2009). In July 2010, she appeared in Once Upon a Time in Mumbaai with Ajay Devgan, Emraan Hashmi and Kangana Ranaut.

In 2012, she appeared in Teri Meri Kahaani in a cameo role. Desai then appeared in a full-fledged role in Bol Bachchan opposite Abhishek Bachchan, along with Ajay Devgn and Asin. The film proved to be Desai's biggest box office success till date.

Desai next appeared in I, Me Aur Main (2013) with John Abraham and Chitrangada Singh. She did another film Policegiri with Sanjay Dutt. In 2014, she appeared in an item number for Ek Villain in a song called "Awari".

In 2016, Desai played former cricket captain Mohammad Azharuddin’s wife Naureen in his biopic film Azhar opposite Emraan Hashmi. She again played the wife of Farhan Akhtar in Rock On 2 a sequel to Rock On!!. The film was released on 11 November 2016.

Desai also worked in the TV series Kasauti Zindagi Ki as Prachi Chauhan. Her role was a cameo only. She also did a two-day cameo in Kasautii Zindagii Kay, which was aired on Star Plus. She played a school student in Prerna’s school.