[3] Sampath was born in the town of Erode, Madras Presidency as the son of E. V. Krishnasamy, the elder brother of Periyar E. V. Ramasamy in 1926.
[3] In the year 1946 Sampath married Sulochana the daughter of Thirupathur G. Samy Naidu who was one of the pillars of the Justice party.
[11] However, faced with the reality of an independent India setting in motion the democratic process under a new Constitution, DMK preferred to keep the separatist issue on the backburner.
The latter preferred constitutional means in pursuing a Tamil state and was keen on contesting in elections for the same.
Sampath found Annadurai too moderate and pressed for more radical policies, direct actions and militant methods.
Sampath later started Congress journals namely Tamil Cheithi, Jayaberigai (Dailies) and Alaigal (Weekly), but incurred heavy financial losses.
To ensure the victory of the Congress Parliament candidates in Tamil Nadu, Indira Gandhi entrusted the entire election responsibility in the hands of Sampath in the year 1977.
Sampath was made secretary of the Tamil Nadu Congress Committee and later appointed as the vice-president of the TNCC.