Dee ihe ọzọ maka paragraf a - N'ọnwa Ọktoba 1939, a họpụtara Mills na Second Australian Imperial Force ma jee ozi na 6th Divisional Reconnaissance Cavalry Regiment. N'agha a lụrụ na Bardia
na Jenụwarị 1941 o duziri ndị agha atọ nke ndị na-ebu egbe Bren ma nye ya ihe nrite Military Cross maka obi ike n'ọgbọ agha. N'oge mwakpo nke Syria na June n'afọ ahụ, e nyere ya Bar na Military Cross ya. Mills bụ onye mbụ n'ime naanị ndị agha iri na ise nke Australia nwere ihe ùgwù ahụ na Agha Worldwa nke Abụọ. E buliri ya n'ọkwa onye isi n'ọnwa Juun n'afọ 1941 ma bụrụkwa onye isi n'ọnwa Febụwarị n'afọ 1942 ma n'ọnwa Maachị n'afọ 1943 e buliri ya n'ọkwa lieutenant colonel nwa oge ma mee ya onye isi nke &lt;a href="2/5th%20Armoured%20Regiment%20%28Australia%29"&gt;2/5th Armoured Regiment&lt;/a&gt;. N'ọnwa Mee afọ 1944, Mills ghọrọ onye isi nke &lt;a href="2/4th%20Armoured%20Regiment%20%28Australia%29"&gt;2/4th Armoured Regiment&lt;/a&gt; ma jee ozi na Madang, New Guinea. Ọ hapụrụ iwu nke ndị agha ahụ na February 1946 ma zigara ndị ọrụ nchekwa na 27 Machị.