Schmitt was born as the son of a businessman in Plettenberg, Westphalia on July 11, 1888; he studied state theory and law in Berlin, Munich and Strassburg and took his graduation and State promotion exams in Strassburg in 1915.
In 1921, Schmitt became a professor at the university of Greifswald, where he published his essay “Die Diktatur” (“On Dictatorship”), in which he discussed the foundations of the newly-established Weimar Republic, emphasising the office of the Reichspräsident. Although most Anglo-American scholars rate The Concept of the Political as occupying a central place in Schmitts work, this may simply be the result of the historical fact that this work was the first of Schmitts essays to be published in English. In many important ways, On Dictatorship is equally important, as its central theme presages much of Schmitts later work. For Schmitt, a strong dictator could embody the will of the people more effectively than any legislative body, as it can be decisive, whereas parliaments inevitably involve discussion and compromise:
If the constitution of a state is democratic, then every exceptional negation of democratic principles, every exercise of state power independent of the approval of the majority, can be called dictatorship.
States must rule, and rule must be exercised decisively. For Schmitt, every government capable of decisive action must include a dictatorial element within its constitution. Thus, in “Die Diktatur,” we find Schmitt's judgement that dictatorships can be more meaningfully democratic than democracies.
This was followed by another essay in 1922, titled “Politische Theologie” (“Political Theology”); in it, Schmitt, who at the time was working as a professor at the University of Bonn, further substantiated his authoritarian theories, effectively denying free will based on a catholic world view. Another year later, Schmitt defended emerging totalitarian power structures in his paper “Die geistesgeschichtliche Lage des heutigen Parlamentarismus” (roughly: “The Thought-Historical Situation of Today's Parliamentarianism”).
Schmitt changed universities in 1926, when he became professor for law at the Hochschule für Politik in Berlin, and again in 1932, when he accepted a position in Cologne. It was in Cologne, too, that he wrote another paper, “Der Begriff des Politischen” (“The Concept of the Political”), in which he developed his controversial state law theories. Apart from his academic funtions, Schmitt was counsel for the Reich government in the case “Preussen contra Reich” when the SPD led Prussian government disputed its dismissal by the right-wing von Papen government. One of the counsels for the Prussian government was Hermann Heller. In German history, this sad struggle leading to the de facto destruction of federalism in the Weimar republic is known as the 'Preussenschlag'.
Schmitt's theories in this paper were later used by the Nazis for an ideological foundation of their dictatorship, and Schmitt was later accused of having justified the “Führer” state with regard to legal philosophy. In fact, Schmitt, who became a professor at the University of Berlin in 1933 (a position he held until the end of World War II) joined the NSDAP on May 1, 1933; he quickly was appointed “preußischer Staatsrat” by Hermann Göring and became the president of the “Vereinigung nationalsozialistischer Juristen” (“Union of National-Socialist Jurists”) in November.
Half a year later, in June 1934, Schmitt became editor in chief for the professional newspaper “Deutsche Juristen-Zeitung” (“German jurisprudents' newspaper”); in July 1934, he justified the political murders of the Night of the Long Knives as the “highest form of administrative justice” (“höchste Form administrativer Justiz”).
Schmitt presented himself as a radical anti-semite and also was the chairman of a law teachers' convention in Berlin in October 1936, where he demanded that German law be cleansed from the “Jewish spirit” (“jüdischem Geist”); nevertheless, two months later, in December, the SS publication “Das schwarze Korps” accused Schmitt of being an opportunist and called his anti-semitism a mere mock-up, citing earlier statements in which he criticised the Nazi's racial theories. After this, Schmitt soon lost all of his prominent offices, and retreated from his position as a leading Nazi jurist, although he remained as a professor in Berlin.
In 1945, Schmitt was captured by the American forces; after spending more than a year in an internment camp, he returned to his home town of Plettenberg following his release in 1946. Despite being isolated in the scientific and political community, he continued to study international law from the 1950s on.