Dr Watt was appointed as Secretary of the Department of Defence from 31 August 2009.

Prior to that, Dr Watt was Secretary of the Department of Finance and Deregulation (formerly the Department of Finance and Administration) from 18 January 2002 to 30 August 2009. He became the longest serving Finance Secretary in April 2009.

He was previously Secretary of the Department of Communications, Information Technology and the Arts.

Prior to that, he was Deputy Secretary of the Department of the Prime Minister and Cabinet and Executive Coordinator of the Economic, Industry and Resources Policy Group until March 2001.

Dr Watt was First Assistant Secretary of Economic Division, Department of the Prime Minister and Cabinet, between March 1994 and November 1996.

Prior to that, he was Minister (Economic) at the Embassy of Australia in Washington for two-and-a-half years.

Dr Watt completed the Advanced Management Program at the Harvard Business School from September to November 1999.

Dr Watt is the former chair of the Organisation for Economic Co-operation and Development's (OECD's) Working Party of Senior Budget Officials, and also the former chair of the OECD Asian Senior Budget Officials.

In 2009, Dr Watt was the recipient of La Trobe University's Distinguished Alumni Award.