Otto Mueller was born in Libau in the Sudeten Mountains in 1874. Not very fond of the disciplined studies at grammar school, Mueller liberated himself in 1890 by starting an apprenticeship in lithography. Here, his artistic talent was discovered and his father finally agreed to allow him to study fine arts. From 1894 to 1896 he studied at the Academy of Arts in Dresden, and in 1898 he went to Munich to study. Back in Dresden he met his future wife Maschka Meyerhofer, who became his favourite model. They lived together at various smaller places and travelled frequently. Mueller moved to Berlin in 1908. On the occasion of an exhibition of artists who had been refused by the Secession and had immediatly formed the New Secession in 1910, he met the "Brücke" artists. He joined the association and spent the summer of 1910 in Bohemia with Kirchner. The following year he too searched for the uncorrupted state of the human being in union with nature and worked with Heckel and Kirchner at the Baltic coast and at the Moritzburger Lakes near Dresden. He took part in the two outstanding "Brücke"-exhibitions of the time: At the Galerie Arnold in Dresden in 1910, and at the Berlin art shop Fritz Gurlitt in 1912. At the same time he also exhibited with the artists of the "Blauer Reiter" group.
After the break-up of the group Mueller maintained contact and friendship with the other former members: He went to Fehmarn with Kirchner in the summer of 1913 and continued visiting Heckel until the 1920s in order to work together. After World War I, during which he had fought as a soldier in France and Russia, he became professor at the academy of arts in Breslau where he taught until his death in 1930.