On 6 July 1918 at Villers-Bretonneux, France he performed the deed for which he was awarded the Victoria Cross: Brown had rushed a machine-gun post armed with a hand grenade, taking one officer and 11 men prisoner under heavy machine-gun fire. After this incident Brown remained at the front until the end of the war, and despite being wounded again in August he was promoted to sergeant on 13 September 1918.
Following the war he was repatriated to Australia in late 1919 before being discharged on medical grounds in February 1920.
War Office, 17th August, 1918.
His Majesty the KING has been graciously pleased to approve of the award of the Victoria Cross to the undermentioned Non-commissioned Officers and Man: —
No. 1689A Corporal Walter Ernest Brown, D.C.M., A.I.F.
For most conspicuous bravery and determination when with an advanced party from his battalion which was going into the line in relief.
The company to which he was attached carried out during the night a minor operation resulting in the capture of a small system of enemy trench. Early on the following morning an enemy strong post about seventy. yards distant caused the occupants of the newly captured trench great inconvenience by persistent sniping. Hearing that it had been decided to rush this post, Corporal Brown, on his own initiative, crept out along the shallow trench and made a dash towards the post. An enemy machine gun opened fire from another trench and forced him to take cover. Later he again dashed forward and reached his objective. With a Mills grenade in his hand he stood at the door of a dug-out and called on the occupants to surrender. One of the enemy rushed out, a scuffle ensued, and Corporal Brown knocked him down with his fist. Loud cries of "Kamerad" were then heard, and from the dug-out an officer and eleven, other ranks appeared. This party Corporal Brown brought back as prisoners to our line, the enemy meanwhile from other positions bringing heavy machine-gun fire to bear on the party.