Emil Hertzka's progressive thinking was not limited to the professional level, but he was also far ahead of his time in his private life. Thus, he and his wife Yella had an equal marriage, Yella contributed to the publishing house by interweaving her professional and private contacts, which she had gained through her activities in the International Women's League for Peace and Freedom, and Emil Hertzka supported Yella's commitment to women's rights. In his will, Emil had designated Yella as universal heir, thus securing her substantial influence over the music publishing house. As a major shareholder, she had a seat on the board of directors - and this at a time when women were to be pushed out of trade and commerce following the constitutional amendment of the principle of equality in 1934.

Yella Hertzka had in-depth knowledge of music publishing and was on friendly terms with many of the UE composers. Correspondence with Arnold Schönberg and Alban Berg shows how much they appreciated her. In addition, Yella Hertzka's lively travel activities for the Women's League resulted in numerous synergy effects from which the composers also profited. For example, at the opening of the congress of the International Women's League in Vienna in 1921, a work by Johanna Müller-Hermann was performed, whose String Quartet op. 6 had been published by the UE years earlier.

With the annexation of Austria to Germany, radical changes took place at Universal Edition. A provisional administrator was appointed and the predominantly Jewish shareholders had to sell their shares cheaply. Yella Hertzka fled into exile in London. Likewise, Alfred A. Kalmus, one of the managing directors of Universal Edition and Yella Hertzka's nephew, correctly assessed the political events and left Vienna to settle in London in the mid-1930s in order to found a branch of Universal Edition there. The aim was to attract new composers to the publishing house and to promote those works whose distribution was becoming increasingly difficult as a result of Nazi cultural policy.

In Vienna, Alfred Schlee and his colleagues brought valuable sheet music by "degenerate" composers to safety and thus maintained the publishing house's line to a limited extent. Immediately after the end of the war, UE continued its tradition as a publisher of the latest music.

In the course of efforts to unbundle Austrian and German publishing, companies that had belonged to Austrians until 13 March 1938 were placed under public administration until the ownership situation was clarified. According to the "Verwaltungsgesetz", the aggrieved owners were to be appointed as public administrators. So, in 1946, Yella Hertzka had herself appointed public administrator of Universal Edition in place of Alfred Schlee and in return appointed him director of Universal Edition. For the next three years, until her death, the management of the music publishing house was in both hands.

Yella Hertzka's commitment to Universal Edition helped to rebuild the relationships that had been severed by the war and the National Socialist persecution of former owners. At the same time, her re-entry into the company also made it easier for Alfred Schlee to re-establish contacts with displaced composers and employees. Furthermore, as a public administrator, she set the course for the restitution proceedings to be carried out in 1951, three years after her death.