Roja was born to Nagaraja Reddy and Lalitha in near Bhakarapeta, Chithoor district, Andhra Pradesh. She has two brothers Kumarasamy and Ramaprasad. She did her Bachelor Degree in Political Science from Sri Padmavathi University. Roja learnt Kuchipudi and was performing dance before she entered films. Roja married popular director R.K. Selvamani on 10 August 2002. The couple have one daughter and one son.
Roja made her acting debut in Telugu films with Prema Thapassu. She was introduced to the Tamil film industry by director R.K. Selvamani with Chembaruthi . The movie was a hit and paved way for role in another success, Suriyan. Her performance in films Veera and Ayudha Poojai were praised. Roja's major career breakthrough was in the film Unnidathil Ennai Koduthen, directed by Vikraman. Roja later appeared in supporting roles in films like Arasu, Parijatham, Shambo Shiva Shambo, Golimar, Mogudu, Kodipunju, Veera, Kaavalan and Saguni (2012). Roja joined Telugu Desam and was the woman wing president of Telugu Mahila Party. In August 2009, she quit TDP and joined Congress Party. She quit Congress party and is now with YSR Congress Party. On 16 May 2014, she won as a MLA from Nagari assembly constituency.