Rome for a short time in 1903 for additional study. From 1910 Müllner was a teacher at the Vienna Academy, and from 1922 he headed the Meisterschule für Bildhauerei there. Josef Müllner is best known for its numerous monuments with religious, mythological or historical subjects. These memorials are often heroic or tragic by nature. His small sculptures are often light-footed: representations of animals, figures and genre scenes.