Nellai Siva is a famous comedian and a supporting actor, who predominantly works in Kollywood cinemas. He works mostly in comedy scenes. One of the outstanding comedy scene with comedian Vadivelu is in the movie
Kannum Kannum. He started his career in the year 2000 with the film Vetri Kodi Kattu as a tea shop owner. After this movie, he slowly got progressed by acting in big movies like Saamy, which had actor Vikram in the lead,
Anbe Sivam with
Kamal Haasan in the lead, Thirupaachi with Vijay in the lead, Kireedam with actor
Ajith Kumar in the lead and much more.
His way of speaking in the movies is completely of Nellai slang, which shows him unique from other supporting actors. He played the role of mechanic in the movie Padikkathavan, which had actor Dhanush in the lead. He played the role of a policeman in two flicks titled Saguni and Kazhugu. He even played a role in director cum actor S J Suriya's movie A Aah (Anbe Aaruyire).