[1] He was a professor of criminal and international law, a member of the Hague Arbitration Tribunal, and served as the last Minister-President of Austria (or Cisleithania) for a few weeks in October and November 1918.

Upon the early death of his father, Lammasch attended the Schottengymnasium and studied law at the University of Vienna, obtaining his doctorate in 1876.

Having traveled extensively through Germany, France and the United Kingdom, he qualified for the criminal law teaching faculty at the Vienna University in 1879.

In the last days of the war, Lammasch was appointed Minister-President by Emperor Charles I on 27 October 1918, succeeding Baron Max Hussarek von Heinlein.

Charles' empire was effectively reduced to the mostly German-speaking Alpine and Danubian crown lands, and the government's authority was even being challenged there by the state council elected by the Provisional National Assembly of German-Austria.

Accordingly, on 11 November, Charles issued a statement in which he acknowledged Austria's right to determine the form of the state and relinquished his right to take part in the country's politics.