After completing Chemical Engineering, Karthik along with his friend Sunil Vishnu quit their respective jobs and started the event management company "Evam" where they organise English plays. Karthik made his acting debut with Alaipayuthey (2000) portraying a small role as Shalini's prospective suitor. He then went on to portray supporting roles notably in films like Yaaradi Nee Mohini (2008) and Poi Solla Porom (2008).In November 2016, Karthik expressed regret for getting typecast in particular roles and threatened to quit the industry.