Through a magnanimous relative, Eysler met the librettist Ignaz Schnitzer, who was compiling the text for Zigeunerbaron (Gypsy King).

Originally, the work was supposed to be staged at the Vienna Court Opera upon completion, but it was spurned by the director for having overly simple music.

Eysler composed the operetta Der unsterbliche Lump (The Immortal Blight), with a libretto by Felix Dörmann [de], for the Vienna Bürgertheater.

Even during the years of World War I, more and more of Eysler's operettas were staged at the Vienna Bürgertheater every season, such as Frühling am Rhein (Rhine Spring), Die – oder Keine!

Due to Eysler's Jewish background, his works were banned from being performed by the Nazis, leading Adolf Hitler to discover that his favourite operetta, Die gold'ne Meisterin, was by a Jew.

For his 75th birthday, he was given the Ring of Honour by the city, and the memorial plaque on his birthplace in Thelemanngasse, which had been removed during the time of the Nazis, was reinstated.