[2] Following the outbreak of World War I, Blain served as a corporal in the 32nd Battalion of the First Australian Imperial Force in France from 1916 to 1919,[3] during which he was wounded twice.

[4] Blain's work took him throughout northern Australia, giving him the opportunity to gain a high profile, which he used at the 1934 federal election, when, standing as an independent for the Division of Northern Territory, Blain defeated the incumbent Labor member Harold Nelson.

After changing his year of birth to 1897,[2] Blain enrolled in the Army during World War II and served as a sergeant in the 2/12 Field Company, Royal Australian Engineers (part of the ill-fated 8th Division, AIF) and sent to Malaya.

[6] During his time as a POW in Borneo he was tortured by the Japanese military police for planning to escape and sentenced to eighteen months in prison.

[2] Blain returned to Australia, and upon re-entering the House, wearing his uniform, was the subject of a standing ovation from his fellow members.