He was then made commander of the SD detachment in that jurisdiction (renamed SS-Oberabschnitt (Main District) "Süd" in November 1933) and served in that capacity until April 1934.

From 6 July 1940 until the fall of the Nazi regime, Hildebrandt was the Police President of Dessau, though others acted in his place during his long wartime absence.

Hildebrandt next was deployed to the notorious 7th SS Volunteer Mountain Division Prinz Eugen, then engaged in counterinsurgency campaigns against Yugoslav partisans in which many war crimes against civilians took place.

[1] On 20 April 1944, Hildebrandt was promoted to SS-Oberführer and named SS and Police Leader in "Oberitalien-Mitte" (Central Upper Italy) with his headquarters in Bologna and, later, Desenzano del Garda.

[6] The Italian authorities generally had not cooperated in the deportation of Jews from the areas they controlled, but this changed after the fall of the Mussolini regime and the occupation of most of Italy by German forces.

[7] After his Italian posting ended in October 1944, Hildebrandt served until February 1945 as a special duties officer to the HSSPF "Südost," SS-Obergruppenführer Ernst-Heinrich Schmauser in Breslau (today, Wrocław).

His last assignment was in Düsseldorf as a special duties officer to the HSSPF "West," SS-Obergruppenführer Karl Gutenberger, in which post he served until the end of the war in Europe in May 1945.