Rajaji was an accomplished writer both in his mother tongue Tamil as well as English. He was the founder of the Salem Literary Society and regularly participated in its meetings. In 1922, he published a book Siraiyil Tavam (Meditation in jail) which was a day-to-day diary about his first imprisonment from 21 December 1921 to 20 March 1922.


In 1916, Rajaji started the Tamil Scientific Terms Society. This society coined new words in Tamil for terms connected to botany, chemistry, physics, astronomy and mathematics.At about the same time, he called for Tamil to be introduced as the medium of instruction in schools.


In 1951, Rajaji translated the Mahabharata from Sanskrit to English, followed by the Ramayana in 1957. Earlier, in 1955, he had translated Kambar's Tamil Ramayana into English. In 1965, he translated the Thirukkural into English. He also translated the Bhagavad Gita and Upanishads into English. He wrote books on Socrates and Marcus Aurelius in English. Rajaji often regarded his literary works as the best service he had rendered to the people. In 1958, he established the Bharatiya Vidya Bhavan.


Apart from his literary works, Rajaji also composed a devotional song Kurai Onrum Illai devoted to Lord Krishna.This song was set to music and is a regular in most Carnatic concerts. Rajaji composed a benediction hymn which was sung by M. S. Subbulakshmi at the United Nations General Assembly in 1967.