 On 10 April 1918 he was awarded the oak leaves to his Pour le Merite.After the fighting ended and the demobilisation of the high command von Quast relinquished his command and put in the leadership reserve.On 18 January 1919 he was assigned command of "Grenzschutz-Armeeoberkommando Nord" (literally "Border Protection – Army High Command North") as part of the Provisional Reichswehr at Königsberg.