Johnston led the brigade in the Second Battle of Krithia on 8 May, and then the Battle of Chunuk Bair in August. During the latter battle, he displayed poor judgement in coordinating the battalions of the brigade following the initial capture of Chunuk Bair by Malone's Wellington Battalion. Chunuk Bair was lost two days later to the Turks. Johnston, still in poor health, had spells in hospital in September, before leaving Gallipoli altogether in November for Cairo to be with his wife, who later died on 15 December. He was appointed a Companion of the Order of the Bath and mentioned twice in despatches for his conduct during the Gallipoli campaign.