After the academy, Julian Hasler was
commissioned into the 1st Battalion of the
East Kent Regiment, on 19 September 1888, and soon promoted to
lieutenant on 4 February 1892. From 1895 he was almost uninterruptedly in active military service, first with the Chitral Relief Force (1895), then the Northwest Frontier in India 1897-1898, where he participated in the capture of the Tanga Pass, and was promoted to
captain on 12 March 1898. He was seconded for service in West Africa under the
Colonial Office from June 1899, and served in South Africa during the
Second Boer War (1900-1902), where he raised the Hasler's Australian Scouts, following which he received the
brevet rank of
major on 22 August 1902. From January 1903 he was again seconded for service under the Colonial office, and served with the
Northern Nigeria Regiment. In Nigeria he documented a new species of
Red-fronted gazelle. He stayed in West Africa 1903–1910. A brevet lieutenant colonel in April 1906, he was promoted to
major on 7 February 1907, to temporary colonel in September, and to
lieutenant colonel on 4 August 1914. ==First World War==