Sastri was acclaimed for his scholarship and mastery of sources and was a recipient of the third highest Indian civilian honour, the Padma Bhushan.

The same year, he succeeded Sakkottai Krishnaswamy Aiyangar[9] as the Professor of History and Archaeology at the Madras University,[10] a post he held till 1946.

[2] In the summer of 1959, he was a visiting professor at the University of Chicago where he delivered a series of lectures on South Indian History.

[12] Nilakanta Sastri, who was then a young teacher in Thirunelveli, wrote a letter to the newspaper opposing Sarkar's suggestion by saying that "English serves me better as a medium of expression than Tamil – I mean in handling historical subjects.

Venkatachalapathy says, "In the professional historiography in Tamil Nadu practised in the age of K. A. Nilakanta Sastri there was rarely any interrogation of sources (except in terms of authenticity and chronology).

In a preface to the 2013 reprint, historian Sanjay Subrahmanyam describes the book thus ... a classic work, which retains its importance and has never quite been replaced.

[18] According to Subbiah, Sastri's views should be analyzed in the context of the rise of the anti-Brahmin Dravida Nadu movement in the mid-20th century: his assertions overemphasizing the importance of Indo-Aryan and Sanskrit influence in south Indian history can be seen as "his angry and desperate response" against the Dravida Nadu secessionists.