Discharged from army service with a partial disability as a Leutnant of the reserve in March 1919, he returned to teaching in Zippow near Schneidemühl, now Piła in Poland.

During the legal ban on the NSDAP, Hinkler worked as a district leader of Wehrwolf, a nationalist and anti-republican paramilitary military association.

On 10 October 1930, he was elected a member of the Prussian Landtag and he was named Executive Director of the Nazi parliamentary faction, holding this position until February 1933.

[3] Named as a national speaker (Reichsredner) for the Party, he was then granted a leave of absence from his Gauleiter position, and was succeeded by Rudolf Jordan on 19 January 1931.

In this position, Hinkler was responsible for the persecution of Jews, Social Democrats, Communists and all other persons and groups who were considered enemies of the new regime.

On 11 August 1933, he requested that one of his predecessors, the Social Democrat Otto Eggerstedt, police chief of Altona and Wandsbek from 1929 to 1932, be sent to Esterwegen concentration camp and be closely guarded.

[4] On 15 November 1933, Hinkler was briefly appointed head of the Gestapo in Berlin by Hermann Göring as the temporary successor to Rudolf Diels.

Hinkler remained Police President of Altona-Wandsbek and head of the Gestapo there until 31 March 1937, when he lost his position as a result of the territorial reorganization mandated by the Greater Hamburg Act.

[6] Toward the end of the war, as Allied soldiers closed in on him, Hinkler committed suicide by taking poison on 13 April 1945 in Nißmitz near Freyburg.