Grant has extensive experience in the Australian energy industry. He was Managing Director of Origin Energy Limited from February 2000 until his retirement in October 2016. He was formerly General Manager, AGL Gas Companies where he held a number of management positions over a 17 year period.

Grant was elected President of the Business Council of Australia in November 2016. In addition to his role at the Business Council, he is the Chairman of Melanoma Institute of Australia, a Director of the Origin Foundation and is a member of the University of NSW Foundation. He also holds a position as Professor of Energy Engineering in the School of Photovoltaic and Renewable Energy  Engineering at the University of NSW and runs his own advisory business, GK Advisory Pty Ltd.

He is former Chairman of Contact Energy Limited, Oil Company of Australia and the Energy Supply Association of Australia (esaa). He is a former Director of Envestra Limited and the Australian Petroleum Production and Exploration Association Limited (APPEA).

He is a Fellow of Australian Institute of Company Directors.