Dalmiya was born into a Marwari family of the Baniya (tradesman) caste, originally hailing from Sikar in Rajasthan and based in Kolkata for many decades [REF].
Dalmiya was married to Chandralekha Dalmiya (née Ghose), who was born into a land-owning Bengali family of Pathuriaghata belonging to the Kayastha caste.