[1] He fought during World War I as an engineer with the 1st Field Company at the Gallipoli Campaign, where he was mentioned in despatches and awarded the Military Cross.

[2][3] He commanded the 14th Field Company at the Battle of Polygon Wood, for which he was appointed a Companion of the Distinguished Service Order.

Bachtold immigrated to Australia in August 1911 and shortly afterwards became an engineering draftsman with New South Wales Government Railways.

Bachtold participated in the initial landing at ANZAC Cove on 25 April 1915 and was awarded a Military Cross for gallantry under fire and mentioned in despatches.

[13] He acted as the Commander, Royal Engineers, 5th Australian Division four times between April 1917 and January 1918, and was appointed as a Companion of the Distinguished Service Order for gallantry at the Battle of Polygon Wood.

[4] In May 1918, Bachtold became the Commander Royal Engineers, 3rd Australian Division,[14] and was promoted to temporary lieutenant colonel on 8 June 1918.

[15] Bachtold returned to Australia on 8 July 1919 with his wife, Dorothy Garner, whom he had married the previous year.