On 19 July 1870 he joined the 2nd (
Emperor Francis) Regiment of Guards Grenadiers and fought with it in the
Franco-Prussian War. On 12 January 1871 Quast was promoted to Sekondeleutnant and received the
Iron Cross 2nd Class. On 23 September 1879 he was promoted to Premierleutnant. 1887 followed a promotion to Hauptmann, and in 1894 he was made a Major and assigned as battalion-commander in the 2nd Guards Infantry. In 1901 von Quast was promoted to Oberstleutnant and assigned to the staff of 1st (
Emperor Alexander) Guards Grenadiers before becoming commander of his old 2nd Guards Grenadiers with the rank of Oberst on 18 April 1903. As General-major he took command of the 39th Infantry Brigade at
Hannover on 21 May 1907. The following year he was at first assigned as commander of the 3rd Guards Infantry Brigade in
Berlin, then assigned to the 2nd Guard Infantry Brigade in
Potsdam. On 27 July 1910 Quast was tasked with the command of the
36th Infantry Division in
Gdańsk. Shortly afterwards he was promoted to Generalleutnant and given command of the
6th Infantry Division in
Brandenburg City. In March 1913 Quast was named commanding general of the
IX Corps in
Altona, Hamburg. ==First World War==