Johan (also Jan) Hendrik (also Henry, Henri) Junius, journalist, naval officer and student in literature and philosophy, was the son of Reverend Franciscus J.J.A. Junius and his wife Anna M.T.B. Junius, born Vietor. He came to the Cape Colony from the Netherlands in 1860 and in March the next year married Sara Helena Keppel Hesselink in Cape Town. She was an author under the pseudonym "Mimosa". They had two sons and two daughters. One of the daughters, Egberdina Anna (Daisy) Junius, became a well-known author in the Netherlands. The family lived in Prince Albert in 1861 but by 1863 had moved to Letjiesbos, near Beaufort West, where Junius was for some time the editor of the Beaufort West Courier. His wife and children returned to the Netherlands towards the end of the eighteen-eighties, leaving him behind.
In 1882 Junius published a book, De kolonien en staten van Zuid-Afrika (The colonies and states of South Africa), which was a guide for potential settlers. It included an extensive geographical register. Meanwhile he had visited a cave at Wonderfontein, near Carletonville, Transvaal, which he described in a paper in the Tydschrift van het Koningklijk Nederlandsch Aardrijkskundig Genootschap (1883, Vol. 7, pp. 108-116). He produced two further books. One of these, Zonnig Afrika (Sunny Africa, Haarlem 1892) was written in collaboration with either his wife or his daughter Daisy and dealt with his travels and experiences in the Prince Albert and Beaufort West districts. The other, Het leven in Zuid-Afrika (Life in South Africa; Amsterdam, 1896) was probably a later edition of an undated book first published in about 1871.