From 1906 to 1908 he worked as a director at the city theatre in Rostock and the Schillertheater in Berlin, founding at the same time the Federation of German Playwrights (Verband Deutscher Bühnenschriftsteller or VDB).

Dinter took part in World War I as an Oberleutnant in an Alsatian Infantry Regiment Number 136, and was quickly promoted to Hauptmann of the reserve and awarded the Iron Cross, Second Class.

In 1915, he fell ill with cholera, and in 1916 he spent a great deal of time in field hospitals having suffered serious wounds, after which he had to be discharged from the military.

During his stay in the field hospitals, Dinter became familiar with German nationalist and mystic Houston Stewart Chamberlain's writings and quickly became a follower of the völkisch movement.

In 1919 Dinter established himself as a writer in Weimar, after his 1917 anti-Semitic bestseller Die Sünde wider das Blut ("The Sin Against the Blood") came out, which was to sell more than 260,000 copies by 1934, and which vividly set forth in writing the stereotypes of the racial-völkisch perceptions of his time.

Heartened as Dinter was by the great success, this novel became the first instalment in a trilogy later given the name "Die Sünden der Zeit" ("The Sins of the Time").

Thereafter he became a founding member of the Deutsch-Völkische Freiheitspartei ("German- Peoples Freedom Party") and forged closer ties with Adolf Hitler.

In 1927 he founded the Geistchristliche Religionsgemeinschaft ("Spiritual Christian Religion Community"), which in 1934 was given the new name "Deutsche Volkskirche" (German People's Church).

At a membership meeting on 2 August 1928, Dinter called for establishing a Party Senate to advise Hitler on all major policy issues.

Two years later the Reichsschrifttumskammer, Nazi Germany's official writers' association, expelled Dinter, effectively banning him from publishing anything, as one had to be a member to do so.