Gerhard Seifert is considered one of the leading German pathologists of his time. He was not only an outstanding scientist but also shaped the politics of university pathology like hardly anyone else. In the context of a national research project on the role of German pathologists in the Third Reich, it was recently discovered that Seifert had joined the Nazi Party. The present study takes this hitherto unknown fact as an occasion for a closer analysis of Seifert's life and work - with a special focus on the Third Reich; the aim is to clarify (1) when and how Seifert's membership came about and (2) how he dealt with the Nazi era and his own political role in the period after 1945. The present study is based on various archival documents. Furthermore, Seifert's autobiography "A Saxon in Hamburg - A Doctor's Life from East to West" was evaluated and cross-referenced with the archival sources. Last not least a systematic re-analysis of the literature on Seifert was conducted, including eulogies and obituaries on his life and work. It can be shown that Gerhard Seifert was an outstanding scientist - with special merits in the fields of oral pathology (including salivary glands), the pathology of the pancreas, endocrine pathology and osteopathology -, an extensive networker and an enigmatic personality. However, it is also demonstrable that Seifert joined the Nazi Party at the age of 17, remained a member until its abolition at the end of the Second World War, and concealed his party membership after 1945. In this respect, he built his career in postwar Germany on a false statement.