Johan Catharinus Justus Bierens de Haan was born on 17 November 1867 in Leiden, the son of the mathematician David Bierens de Haan (1822 1895). He was a descendent of a well to do Amsterdam merchant family, which brought forth a number of academics around the turn of the century.
Johan chose to study medicine, which he concluded with his thesis Over de stofwisseling bij levercirrhose. He specialized in surgery and worked as army doctor in the years 1899 1901, during the second Boer War in South Africa, in 1912 in the Balkans and from 1915 till 1917 in Paris, where he was on staff at a Dutch hospital. At that time, he is said to have been in contact with Mata Hari, the accused spy.
As early as 1909, Bierens de Haan started to undertake a number of journeys to far off destinations, first to Russia, Persia, Afghanistan and Turkey, then, in 1911, with the Trans Siberian Express, to eastern Russia, China and Japan. In 1920, he left for China and Japan and then visited Burma, India, the Philippines, Indonesia, Thailand en Sri Lanka. Finally, in 1925, he journeyed through Syria, Iraq and Iran. He brought back an interesting collection of Asian artefacts from these travels. He then laid down his work as a surgeon and settled in Amsterdam. He held office on the committees of various art associations and foundations. Bierens de Haan died in Amsterdam on 18 December 1951.