四カ年計画
On 1 April 1933 after the Nazi assumption of power, and due to Adolf Hitler's intervention, Reinhardt became State Secretary in the Reich Ministry of Finance under Johann Ludwig Graf Schwerin von Krosigk succeeding Arthur Zarden, whose incumbency violated Nazi policy, as he was Jewish. Reinhardt would hold this powerful position right through to the end of the regime in 1945. From 1936 to 1942, he was also a member of the General Council of the Four Year Plan.