He is married to Lakshmi Kumari and has three children - two sons and a daughter. His sons Surya Sivakumar and
Karthik Sivakumar are actors. Also, his elder daughter-in-law Jyotika is a famous Kollywood actress. T Sivakumar is a devotee of Lord Sri Murugan. He is ambidextrous which means he can use both his left and right hand equally well.
He entered into the industry in 1965 as a supporting actor. But in the late 1960s, he performed as the lead hero in a few Tamil movies namely Kandan Karunai, Uyarndha Manidhan and Thunivae Thozhan. Till 1974, he was seen as a supporting actor in films with M.G. Ramachandran,
Gemini Ganesan, Shivaji Ganesan and R. Muthuraman in the leading roles.
He also performed supporting roles in 7 movies with Jayalalithaa. But after 1974, he introduced himself to his fans as the lead actor in films like Gumasthavin Magal, Arangetram, Panathukkaga, Pattikkaattu Raja, Melnaattu Marumagal, Sindhudhe Vaanam and Bhadrakali.
He also worked in the lead role with the director duo of Devaraj and Mohan in films like
Ponnukku Thanga Manasu, Annakili,
Uravadum Nenjam, Kavikkuyil, and Poonthalir. In fact, Sivakumar has been found performing as the lead actor in movies where
Kamal Haasan and Rajinikanth performed as supporting actors.
Sivakumar was a leading actor in Kollywood and acted in successful movies like Annakili, Rosaappo Ravikkai Kaari, and
Sindhu Bhairavi. Till today, Sivakumar has shown his talent in more than 200 films. He has performed with the three generations of Tamil actors including
Sivaji Ganesan, Prabhu Ganesan, Mohan,
Arjun Sarja, S.S Rajendran, Geminin Ganesan, Rajinikanth and many more. He won Filmfare Award twice for his marvelous performances in Rosaappo Ravikkai Kaari, and Vandichakkaram. He also received Tamil Nadu State Film Award twice for being the best actor in the films
Avan Aval Adhu and Agni Sakshi.
He won the Golden Lotus Award for the movies- Marupakkam and Sindhu Bhairavi. He has always been successful in showing how versatile he is as an actor. He even started working in the television serials in the late 1990s and is famous for his role as Raadhika's husband in the well know TV serial 'Chithi.’ Recently, he ventured into public speaking, expressing his views on several subjects including Hindu Theology. He has been praised for his fluent and wonderful speeches.
Also, he has expressed his views on Mahabharata and Ramayana. In an interview, he once mentioned a very psychological thing saying that achieving peace of mind is probably one of the greatest achievements, something possible only if an individual is satisfied with the success he has accomplished in life.