Sunil Kumar, known by his screen-name Narain, is an Indian film actor, who has starred in Malayalam, Tamil and Telugu films. He made his debut in Adoor Gopalakrishnan's Nizhalkuthu (2002), followed by performances in Malayalam films 4 the People (2004), Achuvinte Amma (2005), and Classmates (2006). Narain's Tamil debut was in Mysskin's Chithiram Pesuthadi (2006).
Narain's first film was Nizhalkuthu. His first commercial film, 4 The People, was dubbed in Tamil and Telugu. He portrayed a struggling lawyer, Emmanuel John, in Achuvinte Amma and also played a doctor, Jeevan, in Sheelabathi. He also played roles in Annorikal and Classmates. His debut Tamil movie was Chithiram Pesuthadi. Through Panthaya Kozhi, produced by director Lal, he has been re-launched as an independent action hero in the Malayalam film industry. In 2008, he did another youth-oriented Malayalam movie Minnaminnikoottam. He has acted in more than 20 Malayalam movies.
Narain worked with director Sathyan Anthikkad in the 2005 movie Achuvinte Amma and again in 2009 in Bhagyadevatha.
Narain played the lead role in P. T. Kunju Muhammed's Veeraputhran (2011). He collaborated with director Mysskin in the 2008 film Anjaathe and in the 2012 superhero film Mugamoodi where he portrayed a villain. However his career high came through the 2019, Lokesh Kanagaraj directed venture Kaithi co starring with Karthi Sivakumar .
Narain completed his pre-degree from St. Thomas College in Thrissur and graduated from Sree Kerala Varma College. On 26 August 2007 he married Malayalam Television host Manju Haridas. Manju had hosted shows like Superstar Junior and has sung in Chithiram Pesuthadi, a Tamil film in which Narain had acted. The couple have a daughter named Tanmayaa.