Radha Mohan Singh was born on 1 September 1949 in Narha Panapur, East Champaran district, Bihar, to Baidya Nath Singh and Jai Sundari Devi. He graduated with a BA from M.S. College, Motihari, under Bihar University. He joined the Rashtriya Swayamsevak Sangh in his youth and began his political career with the Bharatiya Jana Sangh before moving to the BJP.