Ganjawala's first break in Bollywood was Ab Ke Baras in 2002.
Ganjawala has said that he was taken seriously by other music directors because he was working with Barot. His first singing assignment was a Ranjit Barot-composed jingle titled Doodh Doodh for the Operation Flood advertisement. Later, Ganjawala learned music from Bharatiya Vidya Bhavan under the guidance of Sudhindra Bhaumick. With his parents' support he took singing seriously and started believing that he can become a singer. Kunal's sister is a Bharat Natyam exponent, while his father plays the harmonica. Kunal admits that it was his parents' support which made him possible to become a singer. Kunal wanted to be either a chartered accountant or an actor. Since then he started singing at every college festivals and won many intra- and inter-college competitions. He didn't know until college that he could sing. As a child, Kunal Ganjawala never thought of becoming singer.
