Kathiravelupillai was the son of Sivasubramaniam, a proctor from Irupalai in northern Ceylon.

[2] Kathiravelupillai stood as the Illankai Tamil Arasu Kachchi's (Federal Party) candidate in Jaffna at the March 1960 and July 1960 parliamentary elections but on each occasion was defeated by independent candidate Alfred Duraiappah.

[6] Kathiravelupillai played a leading role in the 1961 satyagraha campaign organised by ITAK.

[8][9][10][11] In 1973 Kathiravelupillai published a pamphlet titled A Statement on Eelam: Co-Existence – Not Confrontation, considered one of the most important documents in the Tamil independence movement, which articulated the reasons why the two nations - Tamils and Sinhalese - needed to co-exist on the island of Ceylon in separate states.

[12][13] Kathiravelupillai was the TULF's candidate in Kopay at the 1977 parliamentary election and was re-elected.