At the start of the First World War in 1914, Holland was commissioned a Second Lieutenant in the Interpreters Corps. He later transferred into 114 Battery, XXV Bde Royal Field Artillery. He was demobilised on 27 July 1919 and was awarded an OBE. His brother Cyril had been killed by a German sniper on 9 May 1915, during the Battle of Festubert in France.