Born in Königsberg as the son of the Law professor Gustav Adolf Arndt, he moved to Berlin very early with his family. There, he passed his Abitur at the Gymnasium Philippinum Marburg. Then, Arndt studied Law, Economics and Philosophy at the University of Berlin and the University of Marburg. After passing his second examination and promotion in Marburg in 1927, he worked as a lawyer in the famous law firm of Prof. Dr. Max Alsberg. Since 1932, he worked as a judge, but retired in 1933, stating he did not want to join the Nazi Party. Thus, he joined the law firm of Fritz Schönberg in Berlin, helping (among others) Wilhelm Leuschner and Theodor Leipart. After being classified as half Jewish, Arndt was forced to compulsory labour in the Organisation Todt.
In 1948 and 1949, he was a member of the economic council of the Bizone, chairing the board for law, clerk law and "DM-Eröffnungsbilanz" (statement of the financial conditions for the Deutsche Mark). From 1949-69, Arndt was a member of the Bundestag for the SPD. From 1949-61, he served as corporate attorney and secretary of the SPD faction. In addition to that, he served in 1951/52 as deputy managing director of the Bundestag board for Law and Constitutional law as well as deputy managing director of the Bundestag board for reviewing the administration of the Bund (the so-called Platow-Ausschuss). From 1953-61, he chaired the research group "Rechtswesen" of the SPD faction.
Arndt is most famous for his speech in the debate about statute-barred prosecution of Nazi crimes, in which he states to morally feel guilty about taking part in those crimes.
In many cases, Arndt represented the SPD faction before the Bundesverfassungsgericht.
From March 11, 1963 to March 31, 1964, Arndt served as senator for science and arts in Berlin.
- Warum und wozu Wiedergutmachung?, in: "Juristenzeitung" 1956
- Die Persönlichkeit in der parlamentarischen Demokratie, Berlin, 1958
- Die Entmachtung des Bundestages, in: "Die Neue Gesellschaft", 1959
- Die Nichtigkeit verfassungswidriger Gesetze, in: "Die öffentliche Verwaltung"
- Der Jurist im Parlament, in: "Juristen-Jahrbuch 1960"
- Das nicht erfüllte Grundgesetz, Tübingen, 1960
- Das zeitgerechte Parlamentsgebäude, in: "Die Neue Gesellschaft", 1962
- Gesetzesrecht und Richterrecht, in: "Neue Juristische Wochenschrift", 1963
- Reform der Parlamentarischen Untersuchungsausschüsse, in: "Deutsche Richterzeitung", 1964
- Opposition, in: "Die Neue Sammlung", 1968
Literature about Arndt
- Horst Ehmke, Carlo Schmid, Hans Scharoun (Ed.), Festschrift für Adolf Arndt zum 65. Geburtstag, Frankfurt am Main, 1969.
- Claus Arndt (Ed.): Adolf Arndt zum 90. Geburtstag - Dokumentation der Festakademie in der Katholischen Akademie Hamburg, Kath. Akademie Hamburg und Friedrich-Ebert-Stiftung, 1995