Herman was born on 17 March 1886 in Zagreb to Croatian Jewish family of Danijel and Jozefina Herman. His father died when he was 4 years old. He initially attended business school in Zagreb, although his interest was in drawing and painting. He studied art at the painting school of K. Filip in Zagreb. 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 1905 he enrolled in the Academy of Fine Arts in Munich, where he studied until 1910 under teachers such as Hugo von Habermann. At that time Munich was a center of European art scene for Realism, Post-Impressionism, Symbolism and Jugendstil.

In 1914, after the start of World War I, Herman returned to Zagreb. Being partially unfit for military service, he served the army in Zagreb, from 1915 to 1918. He then went to Munich again, where he continued to live until 1933, with short stays in Zagreb, Berlin and Paris. At that point, due to the escalation of Nazism, he returned to Zagreb. During his stay in Munich he regularly displayed his work, with some success, at solo shows as well as participating in exhibitions of Munich Secession Art.

In 1944, Herman returned to Croatia and rejoined the Partisans. In 1945 he started work as a curator at the Modern Gallery in Zagreb, a position he held until his retirement in 1954. That year he prepared a retrospective exhibition at the Museum of Arts and Crafts, and in 1971 a major retrospective at the Art Pavilion. Herman was a reclusive artist, so his work was late in being accepted and understood.

Herman’s 1973 painting Dva stabla pod brijegom (Two Trees at the Foot of a Hill) was featured on a stamp in the series Croatian Modern Paintings issued 2008.

Herman died on 22 January 1974 in Zagreb and was buried at the Mirogoj Cemetery.