Rajesh Singh was born in Hazaribagh in Jharkhand, India. From a very early age, he bore a passion for acting, but he failed to express his desires to his family. However, when he grew up, his father himself asked him to follow his heart and become an actor, following which he completed an acting course from Asha Chandra Institute and shifted base permanently to Mumbai. A trained actor, Rajesh Singh has done over 15 plays in Prithvi Theatre and several others in venues like Dina Nath Mangeshkar and Ravindra Natya Mandir. He has starred in famous plays like Aadhe-Adhure, Mann Ka Bhoot and Krishna Avatar. He has played mythological characters such as Kumbhkaran in Ravan, Bhim in Jai Hanuman and Ravana in Brahma Vishnu Mahesh. His most famous role is that of Sabu in the beloved TV serial Chacha Chaudhary alongside Raghubir Yadav. Rajesh Singh has also acted in Bhojpuri films Nahiya Lagoni Saiya Se and Egg Chumma Deyi De. He will soon be seen acting in the play Raju Raja Ram Aur Main with Sharman Joshi. Rajesh Singh is a strong believer in Hindu Mythology and believes in existence of 84 lakh rebirths. His 2017 release includes Ti Ani Itar. His 2021 release includes Dilli Kaand.