In 1912, he was the first artist to exhibit an abstract painting in public, at the Salon d’Automne in Paris. Apollinaire spoke of Orphism.

Paradoxically, this anti-militarist joined the Foreign Legion in 1914, like many French Czechs hostile to the Austro-Hungarian Empire. Later, he was one of the organisers of the Czechoslovak army created in December 1917. Very temporarily back in Prague in 1919, he met the wealthy industrialist Jindřich Waldes, who became his loyal patron. From 1920 onwards, in his house in Puteaux, he devoted himself almost exclusively to abstract painting. As a professor at the Prague Academy of Fine Arts staying in Paris, he was responsible for introducing Czech scholarship holders to French culture. His first biography was published in 1922.

In 1925, he became close to the Lille review Vouloir. He was also a member of the Abstraction-Création movement from 1931 to 1934. This solitary artist, constantly on the lookout, did not receive the recognition he deserved in France, despite a joint exhibition with Alfons Mucha at the Jeu de Paume in 1936. It was only after his death, in 1958, that a retrospective exhibition was devoted to him at the Musée National d’Art Moderne in Paris. Today, he is regarded as the greatest Czech painter and one of the pioneers of abstraction.