His father was a physician, and Hermann showed an interest in collecting specimens and in the natural sciences while a boy.
In 1885, he became a scientific assistant at the anatomical institute under Heinrich Wilhelm Gottfried von Waldeyer-Hartz, and received an M.D.
In 1888, Klaatsch received a personal invitation to the University of Heidelberg from the old college friend who had first interested him in anatomy.
Klaatsch has a notorious connection with North Queensland for having returned to the Upper Russell River at the end of 1904 where he acquired the mummified body of the 'King of Bellenden Ker', which he sent to Berlin.
Historical evidence shows indigenous peoples opposed the removal of human remains and that there would be dire consequences for doing so.
"[citation needed] Oetteking added, "It may be difficult for us… to realize that a conception of anthropology raising it to the level of an academic science dates back not even a generation (in 1916), and is due to spirits of Klaatsch's type."
A long-term professor of anatomy and physical anthropology, Hermann Klaatsch died unexpectedly in Eisenach in 1916.