Karnik made his directorial debut with the film Kyun! Ho Gaya Na... in 2004 starring Aishwarya Rai and Vivek Oberoi. He produced and directed the film Heroes in 2008. He has also written the story and dialogues of some of his movies. His directorial venture Yamla Pagla Deewana starring Dharmendra, Sunny Deol and Bobby Deol was released on 14 January 2011.