In his political career Baalu went to jail over 20 times for participating in demonstrations and agitations for public cause. He came to political limelight when he was jailed for one year under Maintenance of Internal Security Act of 1976 for protesting against Emergency clamped in the country. Baalu was first elected to Parliament as a member of Rajya Sabha in 1986. He was elected to Lok Sabha in 1996, 1998 and 2004 from Chennai South constituency and from Sriperumbudur constituency in 2009 and 2019. He was Minister of State in the Ministry Petroleum and Natural Gas, also held additional charge of the then Ministry of Non-conventional Energy Sources and 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. T.R. Baalu is the Leader of DMK Parliamentary Party and the Treasurer of the party and is the only DMK member in the 30 member Joint Parliamentary Committee that probes the 2G spectrum case, where three members from DMK, namely A. Raja, Dayanidhi Maran and Kanimozhi are accused. Baalu is one of the prominent leaders to work towards the implementation of Sethusamudram Shipping Canal Project while he was the minister of Shipping.