 Raja was first elected to Parliament as a member of Lok Sabha in 1996 from the Perambalur constituency and was reelected from the same constituency in 1999 and 2004 elections and from Nilgris constituency in 2009.He was Minister of State for Rural development from 1996 to 2000, Minister of State, Health and Family Welfare from September 2000 to May 2004 and a cabinet minister for Environment and Forests from May 2004 to May 2007.He became the cabinet minister for Communication and Information Technology from May 2007, following the resignation of Dayanidhi Maran.