Miller belongs to the Gangulu people from the area of Mount Morgan, near Rockhampton in Central Queensland.

[4] As a career diplomat, Miller was first posted to the High Commission of Australia to Malaysia, where he served from 2000–2003.

[7] In 2010 Miller was appointed as Counsellor and Deputy Head of Mission at the Embassy of Australia to Germany, where he served under Peter Tesch.

[8][7] On 1 April 2013, Australian Foreign Minister Bob Carr appointed Miller as the new Ambassador of Australia to Denmark, with concurrent accreditation to Iceland and Norway, replacing James Choi.

[5][9][10] He later presented his credentials to Norwegian King Harald V on 17 October 2013 and to Icelandic President Ólafur Ragnar Grímsson on 7 December 2013.