Saurabh Chandra Saturday took charge as secretary in the ministry of petroleum and natural gas.
He succeds Vivek Rae, who demitted office on superannuation Friday.
Chandra, a 1978 batch Indian Administrative Service (IAS) officer of the Uttar Pradesh cadre, will serve for more than a year.
Chandra was earlier secretary, department of industrial policy and promotion.
He becomes the topmost officer of the petroleum ministry at a time when it is to launch two key initiatives - the revision of domestic natural gas prices due from April 1, and the 10th round oil and gas block auctions under the New Exploration Licensing Policy (NELP).