 He joined the 9th Battalion, CEF, and variously worked at the 1st Canadian Motor Machine Gun Brigade and at Corps Headquarters.Although he is often incorrectly attributed a Military Cross for actions at the Battle of Passchendaele or the Battle of the Somme, he was twice mentioned in despatches and received the French Croix de guerre.Lawson joined as a private in 1914 and rose to the rank of warrant officer first class before commissioning.