Jensen was born in Jutland, Denmark, in 1879 and died in Brisbane, Qld,on 13 July 1966.
It is not known when he came to Australia but he completed his undergraduate course at Sydney University in 1903. He won the Syme Prize and Medal for best research in Australia. He was Macleay Fellow of the Linnean Society of New South Wales, 1904-08. From 1909 to 1912 he was soil chemist and soil surveyor, Department of Agriculture of New South Wales, then chief Government geologist of the Northern Territory (1912-16) and temporary Government geologist in Queensland (1917-22), after which he spent most of his career as a consulting geologist, but was senior geologist in the Aerial Geophysical Survey of Northern Australia (1938-40) and investigated mica deposits in central Australia for the Commonwealth Government (1942-43).
Throughout his career Jensen took a keen interest in the vegetation, especially eucalypts, of the areas he visited as a geologist. His eucalypt types were collected in the Northern Territory, Queensland and New South Wales. He wrote a very large number of scientific papers and reports, most of which were published in the journals of the Royal and Linnean Societies of New South Wales. In his younger days he had a keen interest in socialism and wrote The Rising Tide, An Exposition of Australian Socialism, published in The Australian Worker (1908); later he unsuccessfully contested several Commonwealth electorates in Queensland.
He is honoured in the name Eucalyptus jensenii Maiden (1922) for which he is also collector of the type.Source: Extracted from: Hall, N. (1978) Botanists of the eucalypts. Commonwealth Scientific and Industrial Research Organisation, Melbourne