Primarily a music director, Mithoon made his singing debut with The Train. Many people think that he has sung only one song in the album Woh Ajnabee. The song "Mausam" is written and composed and sung by Mithoon himself. Various remixes of these songs have also been made. The Train's music album has been positively received & the songs sung by Mithoon are big hits.
His next film score Aggar was received very well because of the fusion of new vocal styles and music. The song "Ke Bin Tere" gathered a lot of airplay and was a hit. He composed two songs – "Maula Mere" and "Tose naina lage re" – for the movie Anwar and both were superhits. His next song "Madno" sung by Kshitij Tarey and Chinmayi from the movie Lamhaa is a melodious soulful track which was aired throughout the nation for a long time. In his next project Murder 2 he composed two songs – "Phir Mohabbat" and "Aye khuda" – and both songs were well received by audience as well as critics. "Phir Mohabbat" is still aired and ranked among the top songs by various radio FM stations and music channels. All his songs are instant hits. He composed one song "Yeh Kasoor" in the film Jism 2 which was sung by Sonu Kakkar. He has also signed a three-film deal with T series. His next full length project was 3G released in January 2013 in which the songs "Kaise Bataaoon" sung by KK and "Khalbali" by Arijit Singh received great accolades in music reviews. In his second project in 2013, he composed one song "Tum Hi Ho" sung by Arijit Singh for the movie Aashiqui 2 and the promo of this song was released on 23 March on YouTube by T-Series. It was a huge hit with the song already crossing 2,000,000 hits within 2 weeks.
Most people among the audience and music critics feel that he is one of the most underrated music composers today. There are not a lot of people who know that he composed the song "Tere bin" which was a huge hit from the movie Bas Ek Pal. His upcoming Bollywood projects are Bhaag Johnny, Shab, Traffic and Yaariyan. Songs of Yaariyan released on 10 December 2013. He has recently composed "Hai Dil Yeh Mera" for Hate Story 2 which is sung by Arijit Singh. In his recent interview he said that he would like to work with Sonu Nigam.
He was earlier supposed to make music for Onir's I Am but it could not work out due to label issues.