rangarajan was born on 12 may 1952 in a family of zamindars of thiruchengode. his grandfather paramasiva subbarayan was the chief minister of madras province from 1925 to 1926 and a cabinet minister under later governments. his uncle, general p.p. kumaramangalam was a veteran of the second world war and a former chief of army staff. rangarajan's father mohan kumaramangalam was an important theorist and organiser of the undivided communist party of india. his mother kalyani mukherjee was the niece of ajoy mukherjee, sometime chief minister of west bengal, and of biswanath mukherjee, husband of the communist ideologue and parliamentarian geeta mukherjee.