He was commander of the 1st Infantry Brigade from February 1917 until he was killed by artillery fire on 8 June 1917, one of three New Zealand brigadier generals who died during the war.

On 5 May 1915, he was appointed commander of the Canterbury Battalion but was severely wounded a month later during a sortie from Quinn's Post[4] as part as a diversionary attack to draw potential Turkish reinforcements away from the Third Battle of Krithia.

In June 1916, he was promoted to lieutenant-colonel and placed in command of the 2nd Auckland Battalion, 2nd Infantry Brigade of the New Zealand Division, then serving in France.

[2] While visiting the Le Moulin de l'Hospice on 8 June 1917, he was killed during an artillery barrage as he stood talking with Major-General Andrew Russell, the commander of the New Zealand Division.

His grave is close to that of Brigadier-General Francis Earl Johnston, Brown's predecessor as commander of the 1st Infantry Brigade.