Karunas, whose real name is Karunanidhi Sethu, began his career as a gaana singer before entering films. His debut in Boys (2003) and subsequent roles in Dindigul Sarathy (2008) and Ambasamudram Ambani (2010) showcased his ability to balance comedy with emotional depth. Over the years, he became a staple in Tamil cinema, appearing in supporting roles while occasionally taking the lead.
Beyond acting, Karunas has worked as a playback singer, composer, and producer. He also entered politics, serving as a Member of the Tamil Nadu Legislative Assembly from Thiruvadanai constituency (2016–2021). His multifaceted career reflects his versatility as an entertainer and leader, making him a respected figure in both cinema and public life.