Macnaghten was commissioned in the
Royal Artillery in November 1892. and was promoted to
lieutenant on 9 November 1895. He served in India (1894–1896), West Africa (1898–1899), and in
South Africa (1900–1902) during the
Second Boer War, when he was promoted to
captain on 18 April 1900 and attached to the Rhodesian Field Force. Following the end of this war, he served in
Somaliland (1903–1904), India (1905–1909), England (1910–1914) and in
France during
World War I where he was awarded two brevets,
CMG,
DSO,
Croix de Guerre and eight mentions in dispatches. He rose to the rank of
colonel. ==Shanghai==