He became a lyricist after jam sessions with Palash Sen, and after discovering the screenplay for the film Gandhi in a New Delhi bookshop, he started writing screenplays, at age 27.[1] He wrote both the screenplay and the lyrics for Jungle (2000), which was directed by Ram Gopal Verma. The second film written by Sahni and directed by Verma, Company (2002), was nominated for eleven Filmfare Awards and won seven of them. Sahni then worked with Dibakar Banerjee in Khosla Ka Ghosla. Since then he continues to work for Yash Raj Films, where he started as a screenwriter for the film Bunty Aur Babli directed by Shaad Ali which was a box office success and a major breakthrough in Abhishek Bachchan's career.
He then wrote the 2007 film Chak De! India, directed by Shimit Amin, who was also an assistant to Ram Gopal Varma before joining Yashraj films. The movie starred Shah Rukh Khan as the coach of Indian hockey team, and was loosely based on the real-life story of Maharaj Krishan Kaushik.[3] He also wrote the screenplay for Aaja Nachle, which was directed by Anil Mehta and which was also released in 2007. Rocket Singh: Salesman of the Year, the third film of Shimit Amin, was released in 2009.
