Career
He was made commander in the navy in 1899, was chief of the hydrographic bureau from 1899 to 1909, and became director of pilots in 1912. He became distinguished for his explorations, especially of the east coast of Greenland. In 1876, he participated in K. J. V. Steenstrup"s geological expedtition to the Julianehåb District.
From 1883 to 1885 he led the Umiak Expedition with T. V. Garde, exploring the east coast of Christian IX Land, as far as 66° 8" North using umiak boats.
The expedition discovered 11 hitherto unknown Inuit communities, numbering 431 inhabitants, and five great ice fiords. The results and observations of the expeditions were published in Den danske Konebaads-Expedition til Grønlands Østkyst 1883-1885 (1889) and Om de geografiske Forhold i dansk Østgrønland (1889).
Cape Gustav Holm is named after him.