Schlegelberger was born into a Protestant salesman's family in Königsberg. He graduated from the University of Königsberg – or according to documents from his trial the University of Leipzig — in 1899 attaining the degree of Doctor of Law. In 1901 Schlegelberger passed the state law examination and became a court Assessor at the Königsberg local court. In 1904 he became a judge at the State Court in Lyck. In early May 1908, he went to the Berlin State Court and in the same year was appointed assistant judge at the Berlin Court of Appeals. In 1914 he was appointed to the Kammergericht Council in Berlin, where he stayed until 1918. On 1 April 1918 Schlegelberger became an associate at the Reich Justice Office. On 1 October of that year, he was appointed to the Secret Government Court and Executive Council. In 1927, he was appointed as Ministerial Director in the RMJ. Schlegelberger had been teaching in the Faculty of Law at the University of Berlin as an honorary professor since 1922. On 10 October 1931 Schlegelberger was appointed State Secretary in the Reich Ministry of Justice under Justice Minister Franz Gürtner and kept this job until Gürtner's death in 1941. On 30 January 1938 Schlegelberger joined the Nazi Party on Adolf Hitler's orders.
In the Nazi Party
Among Schlegelberger's many works in this time was a bill for the introduction of a new national currency which was supposed to end the hyperinflation to which the Reichsmark was prone. After Franz Gürtner's death in 1941, Schlegelberger became provisional Reich Minister of Justice for the years 1941 and 1942, followed then by Otto Thierack. During his time in office the number of death sentences rose sharply. He authored the bills such as the so-called Poland Penal Law Provision under which Poles were executed for tearing down German posters. Schlegelberger's attitude towards his job may be best encapsulated in a letter to Reich Minister and Chief of the Reich Chancellery Hans Heinrich Lammers: However, in a letter to Hans Heinrich Lammers dated 5 April 1942, Schlegelberger suggested some half-Jews be "spared" and given the choice between "evacuation" or sterilization:
The measures for the final solution of the Jewish question should extend only to full Jews and descendants of mixed marriages of the first degree, but should not apply to descendants of mixed marriages of the second degree. With regard to the treatment of Jewish descendants of mixed marriages of the first degree, I agree with the conception of the Reich Minister of the Interior which he expressed in his letter of 16 February 1942, to the effect that the prevention of propagation of these descendants of mixed marriages is to be preferred to their being thrown in with the Jews and evacuated. It follows therefrom that the evacuation of those half-Jews who are no more capable of propagation is obviated from the beginning. There is no national interest in dissolving the marriage between such half-Jews and a full-blooded German. Those half-Jews who are capable of propagation should be given the choice to submit to sterilization or to be evacuated in the same manner as Jews.
Upon his retirement from the position on 20 August 1942, Hitler gave Schlegelberger an endowment of RM 100,000; in 1944, Hitler allowed him to buy an estate with the money, something that only agricultural experts were entitled to under the rules in force at the time. This would later weigh against him at Nuremberg, for it showed that Hitler thought highly of Schlegelberger.
After the war
At the Nuremberg Judges' Trial Schlegelberger was one of the main accused. He was sentenced to life in prison for conspiracy to perpetrate war crimes and crimes against humanity. In the reasons given for the judgment, it says: At the end of the 1945–1947 trials Schlegelberger was sentenced to life in 1947, although in 1950 the 74-year-old Schlegelberger was released owing to incapacity. For years afterward, he drew a monthly pension of DM 2,894. Schlegelberger then lived in Flensburg until his death on 14 December 1970.
