After studying art in Berlin, Citroen became involved with the Dada movement. In 1922 he moved to Weimar to study at the Bauhaus, where he was taught by Paul Klee, Wassily Kandinsky and Johannes Itten, whose teaching had a particularly lasting influence on him. In 1923 he produced Metropolis, one of his best-known photomontages. From the late 1920s he increasingly focused on photography, and in 1933 he co-founded the Nieuwe Kunstschool in Amsterdam with Charles Roelofsz, an art school inspired by Bauhaus teaching that closed in 1937 for lack of funds. From 1935 he taught at the Royal Academy of Art in The Hague, with an interruption during the war, and continued there until 1960. He then returned to painting as his principal activity, becoming particularly known for his portraits.