 In March 2007, Humpherson was appointed to the newly created position of general manager of Government and Public Affairs at the Australian Nuclear Science and Technology Organisation (ANSTO) and was a member of the management committee.Humpherson left ANSTO in late 2010 to establish his own government relations consultancy, Waratah Advisory, in anticipation of an expected Liberal win at the March 2011 NSW election and accepted a position as Chief of Staff to the newly appointed Resources and Energy Minister, Chris Hartcher.In May 2012, Humpherson was accused by members of the state parliamentary opposition for continuing to be listed as the main contact for Waratah Advisory, with calls for his resignation.