Mahto was born in Korba district to Dhaniram and Tulmati Devi Mahto. He earned a B.A.M.S. (Ayurvedacharya) degree from N.P. Awasthi Government Ayurvedic College, Raipur. Before entering politics, he practiced as an Ayurvedic physician and was active in local education and social service organizations, including the Saraswati Shikshan Samiti and Kamla Nehru Mahavidyalaya in Korba.