Acknowledging that he would never be able to secure a living in New York, Macdonald-Wright moved to Los Angeles in 1918. In 1920, with Stieglitz's support, he organized the first exhibition of modern art in Los Angeles, "The Exhibition of American Modernists" at the Los Angeles County Museum of History, Science, and Art, showing his own large-scale abstract synchromies as well as works by John Marin, Arthur Dove, and Marsden Hartley. In 1922, he became the head of the Los Angeles Art Students League. He also became involved in local theater, serving as the director of the Santa Monica Theater Guild as well as writing and directing plays, designing sets, and acting himself.