Kumar joined Indian Administrative Service in 1975 and belongs to the Bihar Cadre. In 1977 he was posted as Sub-Divisional Officer of Samastipur. He then went on to serve various districts of Bihar and
Jharkhand (erstwhile part of Bihar) as
District Magistrate. Between 1988 and 1990 he took central deputation in
Ministry of Water Resources as National Coordinator for an engineers' training program. In 1990 he became PS to then
Finance Minister Yashwant Sinha under
Chandra Shekhar Government. When the government fell in June 1991, he shifted to
Department of Economic Affairs under
Montek Singh Ahluwalia. From 1993 to 1996 he was posted as chief technical adviser to a food aid program - funded jointly by the
World Food Programme and a
Commonwealth institution run by the
British Government - in
Sierra Leone. After returning from Sierra Leone he was posted in Bihar as head of
Bihar State Electricity Board. In 1999, he again went on Central Deputation as Joint Secretary in the Finance Ministry handling external assistance from EC, UK and Canada. He served on this position until 2004 when he was made Director General of Doordarshan. In 2006, he also took additional charge as CEO of
Prasar Bharti. In the same year, he was posted back in Bihar, where he served as State Finance Secretary and IT Secretary, setting up e-governance systems linking the Common Service Centers in
Panchayats, computerizing treasury operations and setting up a comprehensive public finance management system. In 2010, he joined Ministry of Urban Development as Secretary and was also made Chairman of various Metro Rail Corporations of Indian cities such as Delhi, Bangalore, Kolkata and Chennai. In September 2011, he returned to Bihar when he was named
Chief Secretary of the State. He served on this position until his retirement from Indian Administrative Service in 2012. In March 2013, a selection committee headed by then Finance Minister
P. Chidambaram cleared Kumar's name to head
Special Purpose Vehicle to handle the
Goods and Services Tax Network. ==Goods and Services Tax Network (GSTN)==