Thomas Lonergan served in the Australian Army for more than 20 years. Grey-zone, counter-terrorism and other irregular threats were central to his experience, collaborating with policy, inter-agency, allied and Indo-Pacific partners. He continues to work in public policy and actively serves in the Army Reserve.

He is the author of Ambitiously Grey: Pursuing an Active Australian Military Approach in the Grey-Zone, recently published by the United States Studies Centre at the University of Sydney.