Sharma is the son of producer Romesh Sharma. Currently living in India, Karan Sharma has studied International Business and Management Studies at the European Business School London. He is fluent in English and Hindi, and can speak some French. His mother is Mauritian; his father is Indian. His heroes are Amitabh Bachchan and Hrithik Roshan
His first film, released in 2005, was called Dil Jo Bhi Kahey. He starred with Amitabh Bachan, and it was directed by Romesh Sharma. He has also done a French series called C'est la vie, which was telecast in Mauritius in 2003, in which he also spoke French and a Mauritian.