The younger brother of actor Suriya and the youngest son of actor Sivakumar, Karthi initially joined Mani Ratnam as an assistant director. He was offered acting roles and made his acting debut in "Paruthiveeran" in 2007, which garnered critical acclaim and several accolades including the Filmfare Award for Best Actor. His next project was that of the lead role in "Aayirathil Oruvan" (2010), an action-adventure film directed by Selvaraghavan. He achieved consecutive commercial successes with his subsequent releases – "Paiyaa" (2010), "Naan Mahaan Alla" (2010) and "Siruthai" (2011). After appearing in a series of box office flops, he starred in successful films such as "Madras" (2014), "Thozha" (2016), "Theeran Adhigaaram Ondru" (2017), "Kadaikutty Singam" (2018) and "Kaithi" (2019).