Mao Zedong helped found the Chinese Communist Party in 1921 and organized workers and peasants during its early cooperation with the Nationalists. After the alliance collapsed in 1927, he led an unsuccessful uprising and developed rural revolutionary bases. He argued that peasant mobilization and guerrilla warfare could sustain revolution under Chinese conditions.

The Long March of 1934–1935 brought enormous losses but also strengthened Mao's leadership, especially after the Zunyi conference. From the Communist base at Yan'an, he developed political and military strategy during the war against Japan. The party expanded through organization, resistance, and a renewed but uneasy alliance with the Nationalists. Rectification campaigns consolidated ideological discipline and Mao's authority, employing coercion as well as political education. After Japan's defeat, civil war resumed and Communist armies prevailed on the mainland.

Mao proclaimed the People's Republic of China on October 1, 1949. His government pursued land redistribution, industrialization, and the consolidation of party control. Campaigns against perceived enemies involved executions and imprisonment. During the 1950s agriculture was collectivized and private business brought under state control. The Hundred Flowers campaign briefly encouraged criticism, but the subsequent Anti-Rightist campaign punished many who had spoken out.

The Great Leap Forward, launched in 1958, attempted to accelerate production through communes and mass mobilization. Unrealistic targets, coercive grain procurement, disrupted agriculture, and suppression of criticism contributed to a catastrophic famine in which tens of millions died. Mao retained ultimate political authority, although other leaders assumed greater responsibility for recovery.

In 1966 Mao launched the Cultural Revolution, attacking supposed capitalist tendencies and encouraging Red Guards to challenge established officials. Persecution, factional violence, disrupted education, and military intervention transformed Chinese society and destroyed many lives. In foreign affairs, the leadership pursued rapprochement with the United States, symbolized by Richard Nixon's visit in 1972. Mao remained the central figure until his death in 1976. His career created a powerful revolutionary state while imposing policies responsible for mass death, repression, and prolonged upheaval.