In 1911 he published Letter of a Father of our Times in the magazine PAN for which he was accused, tried and later acquitted of the charges of circulating obscene writing.

His essays on various subjects and topics on literature, theatre, music, and fine arts were published in numerous newspapers and magazines throughout Germany and Austria.

In 1919 Eulenberg, together with painters Arthur Kaufmann and Adolf Uzarski, founded the modern union of artists, “Das Junge Rheinland” in Düsseldorf.

He was “sympathizer” of “Die Maler des Jungen Rheinlands”, the painters of the young Rhineland, and was in contact with personalities such as Hermann Hesse, Thomas Mann, Stefan Zweig, Hanns Heinz Ewers, Frank Wedekind, Gerhart Hauptmann, Lulu von Strauß und Torney, Felix Hollaender, Else Lasker-Schüler, Erich Mühsam, Peter Hille, John Henry Mackay, Herwarth Walden, Emil Ludwig, Franz Werfel, Wilhelm Schmidtbonn, and others.

Yet, he stood firm against the threats of party members, who continuously denounced the pacifist and humanist as a “red-haired Jew”.