Samoa was easily occupied on 29 August 1914 and Logan became its Military Administrator; he remained in this capacity for the duration of the war.

Although he was decorated for his services, his administration of Samoa was later criticised, particularly in relation to the handling of the influenza outbreak of November 1918, which led to 7,500 deaths.

[3] The day after the declaration of war, the British Government requested New Zealand seize the wireless station on the island of Samoa, a territory of Imperial Germany.

[4] The occupation of Samoa was actually in accordance with plans laid down prior to the war by the commander of the New Zealand Military Forces, Major General Alexander Godley.

[9] Despite concerns that Vizeadmiral (Vice Admiral) Maximilian von Spee's Pacific Squadron of two armoured cruisers would interfere with proceedings, the SEF arrived at the capital of Samoa, Apia, on 29 August.

It made an unopposed landing, covered by the guns of the accompanying escorts, and secured the Government offices in the town as well as the wireless station several miles away.

Apart from replacing most of the key officials, who were Germans, with New Zealanders, he largely followed existing policies but over time made a series of misjudgements.

[1] Decorated by the British and French governments for his war services, Logan was made a Companion of the Order of the Bath in the 1917 New Year Honours.

[11] He was later awarded the Croix de Chevalier of the Légion d'honneur in December 1919[12] "in recognition of valuable services in Samoa during the first year of the military occupation of that territory.

[1] Discharged from the NZEF in September 1919, Logan returned to his duties with the New Zealand Staff Corps but after a few months he was posted to the retired list.

Beginning to develop a tendency to exaggerate his contributions to the war effort,[1] he wrote a foreword to a history of the Samoa Expeditionary Force, which was published in 1924.