During this time, he took part in three tours to Iraq as a Biological Weapons Chief Inspector for the United Nations Special Commission.
[1][2] He first joined the Western Australia Department of Health in October 2003, where he was in the position of Director, Disaster Preparedness and Management.
In this role, he led an Australian medical team in the Maldives after the 2004 Indian Ocean Tsunami, managed WA's response to the 2005 Bali bombings, led a WA Health team into Indonesia after the 2006 Yogyakarta earthquake and worked as a radiation health adviser to the Australian Embassy after the Fukushima nuclear disaster.
In June 2018, he was appointed Acting Chief Health Officer, after Tarun Weeramanthri went on leave.
[1][2][3] Robertson was a prominent person in Western Australia's COVID-19 response, doing daily press conferences alongside Health Minister Roger Cook and Premier Mark McGowan.