In spite of Heydrich's aforementioned clear rebuke of September 1939 to the effect that the SD's foreign intelligence reports required improvement, Filbert had enjoyed a rapid rise through the SD and the ranks of the SS during the period 1935–1939. After becoming a full-time employee of Jost's Office III (Counterintelligence) in the SD Main Office on 1 March 1935, he had been promoted to the first SS officer rank, namely Untersturmführer (equivalent to second lieutenant), on 1 July 1936 (see Figures 8, 9 and 10). Exactly one month later, he had been appointed head of Main Department 22 (Enemy Intelligence Services) within the SD Main Office. Further promotions followed on 30 January 1937 to Obersturmführer (lieutenant) and on 12 September 1937 to Hauptsturmführer (captain). On 1 March 1938, his superior in Office III, SS-Oberführer Rudolf Fumy, had given Filbert the following appraisal:

Filbert's promotion to Sturmbannführer (major) followed eleven days later. On 30 January 1939 he was promoted again to Obersturmbannführer (lieutenant colonel). With the creation of the RSHA in October 1939, Filbert had been appointed both deputy head of Office VI (SD Overseas), and head of the subordinated Group A, General Tasks. It was at this point, in autumn 1939, that his SS career stagnated. Although it would be more than six years before the Nazi regime collapsed, Filbert would remain at the rank of Obersturmbannführer (see Table 1). The reasons for this sudden halt to his rapid ascent are to be sought less in his professional performance and more in his family circumstances, as we will see.

The years 1937–1939 in particular also saw notable developments in Filbert's personal life. On 15 May 1937 he married Käthe Ilse Frieda Bernicke, born on 4 April 1910 in Groß Rhüden in Lower Saxony (see Figures 11 and 12). The couple's first son, Dieter, was born a year later in Berlin on 21 May 1938. On 27 February 1940, Käthe Filbert would give birth to their second son, Günter.