As a child, Kunal Ganjawala never thought of becoming singer. He didn't know until college that he could sing. Since then he started singing at every college festivals and won many intra- and inter-college competitions.

Ganjawala graduated from St. Peter's School, Mazagaon. Kunal wanted to be either a chartered accountant or an actor. Kunal admits that it was his parents' support which made him possible to become a singer. Kunal's sister is a Bharat Natyam exponent, while his father plays the harmonica. With his parents' support he took singing seriously and started believing that he can become a singer.

Later, Ganjawala learned music from Bharatiya Vidya Bhavan under the guidance of Sudhindra Bhaumick. His first singing assignment was a Ranjit Barot-composed jingle titled Doodh Doodh for the Operation Flood advertisement. Ganjawala has said that he was taken seriously by other music directors because he was working with Barot.
Ganjawala's first break in Bollywood was Ab Ke Baras in 2002. Although the song did not mark him as a prominent singer, it earned him many offers. Thereafter he sang in many movies, such as Saathiya (2002), Indian Babu (2003), Paisa Vasool (2004), Khakee (2004), Rudraksh (2004), Dhoom (2004) and Meenaxi (2004). His breakthrough hit was "Bheege Hont", from the film Murder, which won the 2005 Zee Cine Award Best Playback Singer - Male and IIFA Best Male Playback Award.

Ganjawala entered the Kannada film industry in 2005. His very first song in Kannada, Neene Neene composed by music director R P Patnaik and written by K. Kalyan for the movie Akash, was a hit of the year. His big break in South India came in 2006 from the Kannada blockbuster film Mungaru Male. His song "Onde Ondu Sari" written by Kaviraj and composed by music director Mano Murthy became the biggest hit of the year. It created records, including for highest sales and downloads.

Popular singer Sonu Nigam who is known in South India for his hundreds of Kannada songs, recently composed a theme song for the Karnataka Bulldozer's team in the Celebrity Cricket League. With lyrics by Sowmya Raoh, this was sung by the trio of Ganjawala, Nigam and Raoh. Ganjawala has sung nearly 450 Kannada Songs thus far.

He has participated in Sa Re Ga Ma, an Indian singing talent competition on Zee TV (now Sa Re Ga Ma Pa) when it was hosted by Nigam. He was a judge on Amul Star Voice of India, another singing competition on Star TV, together with Shreya Ghoshal and Pritam.
Since then Ganjawala has worked for many music directors like Anu Malik, Anand-Milind, Nadeem-Shravan, Pritam, Himesh Reshammiya, Ismail Darbar, Shankar-Ehsaan-Loy, Anand Raj Anand, Rajesh Roshan, Viju Shah, Aadesh Shrivastava, Roop Kumar Rathod, Daboo Malik, and Sanjeev-Darshan. Kunal recently sang for Sanjay Leela Bhansali's Saawariya. His numbers from the films Maashah Alaah and Pari were running top on the chart.
Other than Hindi and Kannada, he has also sung in Tamil, Marathi, Punjabi, Odia, Bengali, Telugu, Assamese and Sindhi languages.
His song "Oh my love" from Bengali language movie Amanush Jeet Gannguli and "Channa Ve Ghar aa jaa" from a Punjabi album Channa Ve by DJ Anit & Music director Santokh Singh was also a success.
In 2007, he participated in a concert tour in North America, called The Incredibles, also featuring Asha Bhosle, Nigam and Kailash Kher.
On 3 April 2010 he performed at RECSTACY, the annual cultural event of NIT DURGAPUR. On 26 November 2010 he performed at SDM UTSAV, the mega fest event of SDMCET.
In 2005, he married fellow singer Gayatri Iyer. They performed the title track for STAR One's Antakshari together. He is a staunch devotee of Sri Sathya Sai Baba.
Kunal Ganjawala has received the following recognitions:
Hindi SongsNon-film songs"Channa Ve Ghar Aaja Ve" (Punjabi album Channa Ve)"Honey Honey" (Music Video featuring Salman Khan)KannadaBengali"Beporowa Mone" and "Kanamachi To" – Kanamachi (film)"বালিয়ামস" and "Jane Jana" – Macho Mustana"Jani Na" – Faande Poriya Boga Kaande Re"Mon Banjara" and "O Shona E Shona" – Fighter"Amay Ador Kor" – Khokababu (2011)"মনে আলো মেলো হাওয়া" – Kolkata The Metro Life (2011)"Mon Bebagi" – Paglu"O My Love " – Amanush (2010)"O Yara Ve" and "Its Only Pyar" – Dui Prithibi (2010)"Shabba Rabba Reeba Ru", "Ekta Bindas Para" and "Le Chakka" – Le Chakka (2010)"Mon Je Kore Uru Uru" – Mon Je Kore Uru Uru (2010)"Cholche Raban Raj" – Paapi (2010)"Sedin Dekha Hoyechilo" – Sedin Dekha Hoyechilo (2010)"অহনো জেনো" and "করো সালাম" – Wanted (2010)"Mahi Ve"- Challenge"Prem Aamar", "Uru Uru Swapne", "Kon Bhule Tumi", "তুমি ছাড়া আজ একা" and "Shob Rong Muche" – Prem Aamar (2009)"Bande Mataram" – Minister Fatakesto (2007)Tamil'Maa ganga' – Naan Kadavul-Ilayaraja'Spider Man' – New – A.R.Rahman'Please Sir' – Boys – A.R.Rahman'Maaro Maaro' – Boys – A.R.Rahman'Kattikko Rappa Rappa' – Thimiru – Yuvan Shankar Raja'January Madham' – 7G Rainbow Colony – Yuvan Shankar Raja'Yethi Yethi' – Vaaranam Aayiram – Harris Jayaraj'Anbulla Kadhali' – Aalwar – Srikanth DevaTelugu2014 – Heart Attack – "Endhukila Nannu Vedhisthunavey"2010 – Simha – "ఘఙృ"2009 – Taj Mahal – "Etu Chusina"2009 – Arya 2 – "Karige Loga"2009 – Adurs – "Neethone"2009 – Ganesh – "Raja Kumari"2006 – Pokiri – "Jagadame"2005 – Balu abcdefg – "Hyderabadi Ladka"2004 – Nani – "Spiderman"2008 – Ready – "Tu Tu Tu"MarathiVaryavarti Gandh Pasarla – (Sawarkhed..Ek Gaon)Dena Paisa Dena – (Uladhaal)bayago bayago – (Ringa Ringa)Aaicha Gho – (Zabardast)Lai Bhari – (Lai Bhari)Tension chya Bailala DholOath Olawale (Shubhmangal Savdhan)Ti Jakham Juni (Vanshvel)Tu Shwaas Sare (Lagna Pahave Karun)Malayalam"Ekantham Janmam" – 5 Sundarikal – Gopi SunderOdia"Aare Aare Mo Geetare Mitare Aare" – Tumaku Paruni Ta Bhuli"E Jibana Emiti Suna Geetatiere" – Tumaku Paruni Ta BhuliPunjabi2013 – "Pooja Kiven AA" – "Shayad Eh Pyaar""Saadi Love Story" – Title TrackUrduHalla Gulla (2015) - "Halla Gulla", "Thumka"
SelfAnkahee (2006) (uncredited) .... Himself (singing "Tumse Yun Milenge")