A friend and compatriot of Tristan Tzara, he was among the founders of the Dadaist movement at Cabaret Voltaire in Zürich. In 1922, he returned to Romania and worked as an architect and painter. In 1941, he left for Mandate Palestine to escape the Nazis.
In 1953, Janco established the Ein Hod artists' village near Haifa, Israel. Towards the end of his life he helped found the Dada museum in Ein Hod which bears his name. The museum houses Janco's art, explores the history of Dadaism and mounts changing exhibitions.