Dee ihe na-esote paragraf a - Johnston lụrụ ọgụ na Agha Worldwa Mbụ, na-eje ozi n'ihu agha nke Western Front na mbụ Expeditionary Force, na-emerụ ahụ ugboro anọ ma na-arịgo n'ọkwa nke Brigadier General. Na mbido Johnston jere ozi dị ka onye ọrụ mgbaama maka 7 Infantry Brigade. Ọ gara n'ihu na-eje ozi na ikike ahụ na Ngalaba nke 3 tupu ọ bụrụ, Brigade Major, Commanding Officer 10th Battalion Cheshire Regiment na n'ikpeazụ Officer Commanding 126 Infantry Brigade. Johnston sonyere n'agha ndị a lụrụ na Mons, Le Cateau
na ịlaghachi azụ na ọganihu na-esote Aisne. N'afọ 1916, mgbe ọ na-achị ndị 10th Battalion Cheshire Regiment, e nyere ya onyinye Distinguished Service Order (DSO) maka ihe o mere n'agha Somme. Mgbe otu afọ gachara na 1917, a ga-enye ya ọkwa DSO ya maka omume ya na Ypres. N'oge agha ahụ, a kpọtụrụ ya aha na Despatches ọ dịkarịa ala ugboro ise na 1916 e nyere ya Croix de guerre French. Johnston dere ihe ndị o mere n'agha n'akwụkwọ ya.