During an academic career spanning over four decades he wrote about 10 books and over 200 research articles on subjects ranging from his central interest in Smriti literature to "the Vedas, Vyākaraṇas, Kāvya, anthology, archaeology, world-history, paleography, and the Nyāya and Vaiśeṣika systems of philosophy.
He earned a PhD in 1936 under the guidance of S. K. De, while working as a lecturer in Sanskrit and Bengali at the Jagannath Intermediate College.
Hazra obtained a D. Litt in 1940 with his Studies in the Upapuranas, which was incompletely published as a series of books by Munshiram Manoharlal with permission of the then Principal of the Calcutta Sanskrit College and is considered by some to be his magnum opus.
During this period he, along with fellow faculty-member, R. C. Majumdar, aided revolutionaries fighting for Indian independence from British rule by giving them shelter in the university's Dacca Hall, where Hazra was the provost.
He was elected a fellow of The Asiatic Society in 1964 and later awarded its S. C. Chakravorty Medal for "outstanding contribution in Ancient Indian Language with special reference to Smriti and Purana" and its Naresh Ch.