Tiruchelvam and his brother Rajendra were sent to British Ceylon to have their education at S. Thomas' College, Mount Lavinia.

He was one of the defence lawyers in the 1976 Trial-At-Bar of Appapillai Amirthalingam, K. P. Ratnam, Murugesu Sivasithamparam and Kathiripillai Thurairatnam, four leading TULF politicians who were charged with sedition for defying the First Republican Constitution.

72 Tamil lawyers took part in the defence, including S. J. V. Chelvanayakam and G. G. Ponnambalam, two leading lawyer-politicians.

Tiruchelvam also defended Junius Richard Jayewardene when he was threatened with expulsion from the United National Party in 1972.

Tiruchelvam and other ITAK leaders were jailed in 1961 for staging a mass satyagraha against the Sinhala Only Act.

ITAK's MP refused take ministerial portfolios but instead Tiruchelvam was appointed to the Senate of Ceylon and made Cabinet Minister of Local Government.

His son Neelan Tiruchelvam, became a leading human rights activist and member of parliament