Many Chinese intellectuals believed that the US had done little to sell the Fourteen Points, among them self-determination, at Paris, and observed that the US itself had declined to join the League of Nations; as a result they turned away from the Western liberal democratic model. Marxism began to take hold in Chinese intellectual thought and communism began to be studied seriously by some Chinese intellectuals such as Chen Duxiu and Li Dazhao.

The Chinese Communist Party (CCP) traces its roots back to 1917, when its founders were inspired by the Bolshevik victory of the 1917 Russian Revolution. They saw Communist Revolution as an alternative response to colonialism. Li Dazhao, a future co-founder of the CCP, became chief librarian at Peking University (Beida) in 1918 and headed a Marxist study group, influencing several students, including Mao Zedong, who participated in the May Fourth Movement of 1919. Chen Duxiu, another future co-founder of the CCP, and a leader of the May Fourth Movement for Science and Democracy, attended Li's study group in 1919. Chen founded a magazine, La Jeunesse (New Youth – 新青年), to spread these new ideas. 

The Comintern (Communist International), founded by Vladimir Lenin, sent agents to China in May 1919. The agents found two revolutionary movements (the study group at Beida and Sun Yat-sen's Republican movement). Comintern representatives met with Li Dazhao and Chen Duxiu but, unimpressed by their naiveté and small core of followers, gave them instructions in Theory and Practice.

The official founding and First Congress of the CCP took place in July 1921, at a girls' school in Shanghai's French Concession. Twelve delegates and fifty party members attended. During the meeting, the school was raided, and the delegates fled and reassembled on a pleasure boat on South Lake in Zhejiang. Mao Zedong was among the attendees, and two years later, he was elected to the Central Committee. Over the next decade, Mao formulated his ideas on the role of the peasant (as opposed to the urban working class) as the vanguard of revolution.