Lok Sabha in 1996 from Chennai South constituency and became Minister of State in the Ministry Petroleum and Natural Gas. Towards the end of his tenure, he also held additional charge of the then Ministry of Non-conventional Energy Sources (now called the Ministry of New and Renewable Energy). Baalu was re-elected to Lok Sabha in 1998, 1999 and 2004 from the same constituency and again in 2009 and 2019 from Sriperumbudur constituency. Baalu served as Cabinet Minister of Environment and Forests from 1999 to December 2003 and as Minister of Shipping and Road Transport and Highways from 2004 to 2009.