Hugo's father died in 1862 and in 1863 his mother married her husband's brother, Leopold Preuß (1827–1905), a well-off grain merchant.

[2][3] Although the quality of his writings was appreciated by academia, his Jewish religion and democratic-liberal views prevented him from becoming a tenured professor at the conservative Berlin university.

[3] Only a few days after the abdication of Emperor Wilhelm II had been announced during the German Revolution of 1918–19, Preuß, in an article published on 14 November 1918, called on the middle-classes to "accept facts" and cooperate in creating a republic.

On 15 November, the head of the revolutionary government, Friedrich Ebert of the Social Democratic Party of Germany (SPD), appointed Preuß state secretary of the Ministry of the Interior.

Under the old imperial constitution, the state secretaries had been the heads of the various departments, not true ministers but more senior civil servants working for the chancellor.

[2] Preuß vehemently opposed the Triple Entente's prohibition of the incorporation of German Austria into Germany as a contradiction of the Wilsonian principle of self-determination of peoples.

He also was unable to put into practice his idea of a very narrow definition of fundamental rights, limited to the classical freedoms, which he wanted to codify in just three articles of the constitution.

Some parts of the Weimar Constitution (on the role of parliament, government and president) that are considered especially problematic in hindsight were strongly shaped by his ideas.

He felt it was a necessary precaution to deal with the danger of a dictatorship of the parliamentary majority and to resolve conflicts between government and parliament by the most democratic method available—through new elections.

Preuß also was pessimistic about the ability of the political parties to operate successfully within the new framework: they had no experience in taking on responsibility or making the sorts of compromises required for stable government.