The Tübingen Prehistoric Research Institute (Tübinger Urgeschichtliche Forschungsinstitut ) under the direction of Robert Rudolf Schmidt carried out extensive excavations at the Federsee, where Reinerth soon played an important role.

He became editor of the magazines Germanen-Erbe and Mannus, Zeitschrift für Deutsche Vorgeschichte and in addition was department head for pre- and early history with the Nationalsozialistischen Kulturgemeinde, the successor organization of the Kampfbund.

"[1][2] In June 1938, with the Gauleiter of Baden Robert Wagner in attendance, Reinerth inaugurated an open-air museum he had designed with fourteen reconstructed Stone Age huts in Radolfzell.

[2] From 1940 Reinerth served as head of a special prehistory staff for the Reichsleiter Rosenberg Taskforce (ERR), which expropriated so-called "ownerless cultural property of Jews", whose owners had usually been previously killed.

[3] In September 1942 Rosenberg assembled a "Working Group for Greek-Iranian Antiquity Research in the Occupied Eastern Territories", as a branch of the Institute of Indo-European Intellectual History, based in Munich.

Between 1954 and 1958 Reinerth was the first chairman of the newly founded Association of German Scuba Divers (Verband Deutscher Sporttaucher-VDST) In 1958 he was appointed Honorary President of the VDST.