 On the conclusion of the war he rejoined the Staff College, which he had entered in 1901, and passed out in 1903.Obtaining his Majority on transfer to the Irish Guards in 1906, he was next a General Staff Officer at the Army Staff College from 1908–1911, finally becoming Lieutenant-Colonel when succeeding Charles FitzClarence to the command of the 1st Battalion, Irish Guards in July 1913.Morris took his battalion to France on 12 August 1914, at the outbreak of World War I and was killed in action on 1 September, during the Retreat from Mons when the 4th (Guards) Brigade formed a rear-guard for the 2nd Division in La forêt de Retz near Villers-Cotterêts  where he is buried in the Guards' Grave.