Manjhi was born on 6 October 1944 in Mahakar village under Khijarsarai area in Gaya district of Bihar.[11][12][13] His father Ramjit Ram Manjhi and mother Sukri Devi were farm labourers belonging to the Musahar community. He was tutored by an upper caste teacher after getting the permission of his upper-caste landlord until 7th class. After completing his graduation from Magadh University, he worked at the Gaya telephone exchange for 13 years until his younger brother became a policeman.[14] He is married to Shanti Devi; the couple has two sons and five daughters.[12] One of his sons, Santosh Suman Manjhi, is an MLC.