He was born on September 22, 1869. Born in the village of Valangaiman, near Kumbakonam, to the poor Vaidik Sankaranarayana Sastri, Sastri had a brilliant stint at the Native High School, Kumbakonam, and then in the government college in the same town. Starting his life as a teacher he became the headmaster of the Hindu High School, Triplicane. His eight-year service there was memorable. Besides giving the students his attractive teaching of English and Sanskrit and the school his able administration, he gave the teaching community an organisation — the Madras Teachers Guild — to fight for their rights. It was he who founded the Triplicane Urban Co-operative Society, long before the government thought of starting co-operative societies in the State.
He gave up the profession he greatly loved to join the Servants of India Society started by Gokhale. Here the co-disciples Sastri and Gandhiji had so much love and respect for each other that Gandhiji took pride in addressing Sastri as his elder brother in all his correspondence. But this didn't mean that the two had similar views in their approach to the Freedom Struggle. When Gandhiji sought Sastri's advice before launching his non-cooperation movement, he stoutly opposed it warning that disregarding law and order would spell disaster to the country's future.