He fought in the First World War under the 95th Krasnoyarsk Infantry Regiment [et] against the Germans, where he was wounded and concussed.

[3][1] On 1 January 1919, Koch was recommissioned into the 2nd Infantry Regiment, where he was promoted to Captain for exemplary service on 25 September 1919.

[3][5] Koch took part in battles near Pada Manor, Paju, Kriuši, Narva, Luga River, and Krasnaya Gorka.

[6] At the end of the war, Koch was awarded with the Cross of Liberty, Second Class, Third Rank on 17 August 1920.

[1] Koch was promoted to Lieutenant Colonel on 30 January 1924, and he was appointed commander of the 1st Battalion of the 1st Infantry Regiment in March 1924.