Gustav Adolph Ettling came to South Africa before or in 1887 and became a naturalized citizen (of the United Kingdom) while residing in the Cape Colony in 1891. He was a printer in Kimberley from about 1892. From 1903 his firm was described in the General Directory of South Africa as the "Electric printing works, bookbinder and india rubber stamp manufacturer, Kimberley". The earliest known work that he printed was a report on the South African and International Exhibition held in Kimberley in 1892. He remained in business through the Anglo-Boer War (1899-1902) and in 1904 printed a handbook on the Kimberley Trades and Industries Exhibition organised by the Young Men's Christian Association.
Ettling assembled a collection of 103 mounted heads and horns of South African antelopes. He bequeathed the collection to the McGregor Museum, which opened in Kimberley in 1908 under the directorship of Miss M. Wilman*. The collection was received in 1908, the year of his death, and put on display the next year. Ettling was not in the Transvaal Colony at the time of his death.