He was influenced by the work of Peter Paul Rubens. During his stay in Paris he encountered Eugène Delacroix and Alexandre-Gabriel Decamps and became familiar with their works. Many of his paintings depicted scenes from Czech history; he was, however, also interested in subjects from Montenegro and Herzegovina, and one of his most famous works is The Wounded Montenegrin. His works are influenced by Romanticism. As an important artistic exponent of the Czech National Revival, he actively participated in the emancipation efforts of Czechs and other small European nations. The themes of his works bear the stamp of anti-Habsburg stance. Čermák painted portraits and genre pieces in addition to history paintings.