Chen Kun and Li Chen respectively play Party founders Chen Duxiu and Li Dazhao. Huang Xuan and Ni Ni star as the couple of Li Da, one of the early Party leaders, and his wife, Wang Huiwu.

Actor Wang Renjun reprises the character of Chairman Mao Zedong after his 2019 military film, The Bugle of Gutian.

Zhu Yilong stars as China's first premier, Zhou Enlai, turning 23 years old in 1921. Wang Yuan plays the role of Chinese leader Deng Xiaoping, then aged 17.

Recalling that he was invited to return to the familiar subject in 2016, director Huang Jianxin, who also serves as the executive producer, says it was stressful to seek a breakthrough in storytelling, as he worried that old-school filmmaking would fail to hook young people, the mainstream theatergoers.