This article explores the relationship between materialism and philosophical idealism in the political philosophy of Marxist revolutionary movements, by illuminating the influence of Neo-Confucian idealism on the sinification of Marxism. Although they had virtually no access to the writings of the young Marx, Li Dazhao and Mao Zedong incorporated idealist philosophical ideas into their sinified Marxism. I argue that three elements of Neo-Confucian idealism contributed to the sinification of Marxism that emerged by the 1940s: (1) acknowledgment of the real existence of the material world as apprehended by the mind-and-heart in Zhu Xi’s Neo-Confucianism; (2) emphasis on human will and consciousness, drawn from Wang Yangming’s Neo-Confucianism; and (3) recognition of an autonomous, even decisive role of consciousness and culture in revolutionary change. The resulting sinified Marxism constituted a revolutionary New Confucianism, highlighting the most universal, humanistic, liberative elements in the Chinese philosophical tradition. These community-affirming and spiritually rich elements can be mobilized against authoritarian forces to support the continuing struggle for human rights and democratization within and well beyond China today.