He was appointed the Secretary of the Department of Prime Minister and Cabinet on 6 June 2022, and as of December 2024[update] serves in the role.

[citation needed] For nearly 14 years Davis served as vice-chancellor and Principal of the University of Melbourne and as Professor of Political Science in the Faculty of Arts.

[citation needed] In 2010 Davis presented the ABC's 51st Boyer Lectures series, speaking on higher education in Australia.

[9] In October 2018, Davis joined the Crawford School of Public Policy at the Australian National University as a distinguished professor.

[citation needed] His career memberships include: the chair of Universitas 21, the Association of Pacific Rim Universities steering committee, the Hong Kong Grants Commission, and a director of the Menzies Centre for Australian Studies at King's College London.

[11] On 26 January 2002, Davis was appointed a Companion of the Order of Australia for his "service to public administration, particularly as an advocate for good governance, constitutional reform and the creation of infrastructure to enable the development of a "knowledge-based" nation, to tertiary education in the field of political science, and to the community.

[citation needed] As of 2005[update] Davis is married to Margaret Gardner, the 30th Governor of Victoria and former Vice-Chancellor of Monash University and RMIT.