After obtaining his Doctor's Degree in 1855, he moved to Berlin, where he continued his Sanskrit studies as a pupil of Albrecht Weber, and also took up Germanic and Slavonic languages.

Together with Herman Neubronner van der Tuuk, Kern is regarded as one of the founding fathers of Oriental Studies in the Netherlands.

His thesis, entitled Specimen historicum exhibens scriptores Graecos de rebus Persicis Achaemenidarum monumentis collatos (1855) broadened the field to Persian, showing that inscriptions in that language could now be used to extend our knowledge of Ancient Persia.

In 1879 he worked on Cambodian inscriptions, then turned his attention to Kawi (or Old Javanese) and in 1886 showed that Fijian and Polynesian were cognate languages.

Thus, in 1889 he made use of the "Wörter und Sachen" method (which compares designations for plants, animals and objects in cognate languages) to ascertain a putative dispersal centre for the "Malayo-Polynesian" peoples.

21 of Max Müller's Sacred Books of the East); and a Manual of Indian Buddhism (Strassburg, 1896) for Buhler Kielhorn's Grundriss der indoarischen Philologie.

[2] He also critically edited the Jataka-Mala of Arya Shura in the original Sanskrit [in Devanagari] which was published as volume 1 of the Harvard Oriental Series in 1891.