Though the film received mixed reviews, his performance was praised. Karthi's "Kaatru Veliyidai", was directed and produced by Mani Ratnam. The film met with mixed reviews and became a failure. Karthi's "Theeran Adhigaaram Ondru" was directed by H. Vinoth and produced by Dream Warrior Pictures. It received critical acclaim and Karthi received a "Filmfare Award South" for the "Best Actor - Critics" for his performance. The film became a huge success at the box office. Right after "Theeran" Karthi acted in "Kadaikutty Singam" portrayed the role of a farmer directed by Pandiraj which has been produced by this brother Suriya which has gained the highest footfalls in the year 2018 in Tamil Nadu. Karthi's next film was "Dev" produced by Prince Pictures, directed by debutante director Rajath Ravishankar, music composed by Harris Jayaraj and R.Velraj handles the camera. The film received negative reviews from critics and eventually became a commercial failure. Karthi is the second son of actor Sivakumar and his wife Lakshmi. He has two siblings; an elder brother, Suriya, who was already an established actor at the time of Karthi's film debut, and a younger sister named Brindha. Tamil film actress Jyothika is Karthi's sister-in-law. On 3 July 2011, Karthi married Ranjani Chinnaswamy, who graduated with a master's degree in English literature from Stella Maris College, Chennai. They were engaged on 29 April 2011 at Ranjani's native village, Goundampalayam in Erode District, and the wedding was held at the CODISSIA trade fair complex in Coimbatore. The wedding was arranged by the elders of the family. They have a daughter named Umayaal, born on 11 January 2013. Karthi has been involved in several charities and social service activities. On his 31st birthday, he inaugurated the "Makkal Nala Mandram", in order to encourage his fans to become involved in welfare activities. During the event, Karthi donated blood, donated bicycles to handicapped people, sewing machines to women and schoolbags to children. He presented a cheque of 50,000 to YRG Care Centre, which helps AIDS affected children. In 2011, Karthi became a cause ambassador for promoting awareness of lysosomal storage disease.