Warren has been a member of a range of Parliamentary Committees over his time in the Parliament, including most relevantly the Joint Committee on Foreign Affairs, Defence and Trade and, more particularly, the Defence Sub Committee.
During the Hawke and Keating Governments, he was Parliamentary Secretary in a range of portfolios, including Parliamentary Secretary to the Minister for Transport and Communications from April 1990 to May 1992; Parliamentary Secretary to the Minister for Employment, Education and Training from May 1992 to March 1996; Parliamentary Secretary to the Minister for Environment, Sport and Territories from April 1993 to December 1993 and from March 1994 to March 1996.
Warren was Minister for a number of Portfolios in the Rudd and Gillard Governments. He was Minister for Defence, Science and Personnel from December 2007 to September 2009 and from September 2010 to September 2013; Minister for Indigenous Health, Rural and Regional Health and Regional Services Delivery from June 2009 to September 2010; Minister for Veterans’ Affairs from September 2010 to September 2013; Minister for Indigenous Health from September 2010; Minister Assisting the Prime Minister on the Centenary of ANZAC from March 2011 to September 2013.