[5] Then he moved to Munich where in 1904, like his compatriot Josip Račić, he attended the school of the Slovene painter and teacher Anton Ažbe.

In the war years, Herman joined Partisan forces and was captured and confined in the Internment camp (1942–44) of Ferramonti di Tarsia, in Calabria, southern Italy.

[10] As a member of the famous Munich Circle, Herman's early work had a strong influence on Croatian contemporary art from the first half of the twentieth century.

[7] As the longest lived member of the group, Oskar Herman had the most time to develop as an artist, yet he remains the least well-known and accepted within Croatia.

Recent acclaimed retrospective exhibitions have shown previously unknown Herman drawings, most of them from the Munich period (1906–1933) and have led to a better appreciation of his work.

[11] While in Munich, Herman encountered the ideas of prominent art historian Julius Meier-Graefe and his aesthetics of "pure visibility".