Forced into hiding, he joined the Republic of China military after the 1911 revolution but left government service and moved to Shanghai after growing disillusioned.

Long interested in Peking opera and other forms of drama, Zheng joined several troupes while also gaining a reputation as a stage performer.

[1] The son of Zheng Moqin, a government official who traced his roots to She County, Anhui,[2] he attended the Jiangnan Military Academy and became a junior officer in the Ninth Division of the New Army.

[3] A 1921 retrospective, published after the overthrow of the Qing dynasty, described him as gaining a hatred of the regime and seeking "the restoration of China as his own duty".

[7] Zheng had an interest in the theatre, including Peking opera, from his youth, and in the 1910s he became a leading member of the Eternal Memory Society fan-club.

While teaching, he also performed on stage, gaining recognition for what the critic Zhou Jianyun deemed a "solemn attitude, upright speech, sense of concision, moderation, and possessing the air of a knowledgeable person".

[13] He had worked with several of them at the Mutual Stock and Produce Exchange Company, which collapsed in 1921,[14] and the men were required to use their own funds as start-up capital after fundraising efforts failed; each contributed 10,000 yuan (equivalent to ¥1,048,000 in 2019).

[20] Zheng gained acclaim for his performance in Labourer's Love, with one critic identifying him as setting a new benchmark for acting and another lauding him as an East-Asian Lewis Stone.

[24] This film, which premiered on 21 December 1923, was an immediate commercial success, running for almost 100 days in Shanghai alone;[25] further screenings were held in Beijing, Nanjing, and Suzhou in subsequent months.

The contemporary critic Linfu wrote in Yingxi Chunqiu, "when Zheng Zhegu died, the Chinese film industry seemed to have lost half of its soul".

[22] In their review of Chinese cinematic history, Chen Jingliang and Zou Jianwen describe Zheng as one of the silent era's most important actors.

Letianxiannong, in a 1925 review of Zheng's career, gave particular praise to his performance in Orphan Rescues Grandfather, claiming that "all the moods of joy, anger, and sorrow are true to life.

[34] In a 1925 Shen Bao article, the reviewer Qiyu praised Zheng as the greatest of China's male actors, writing that he was the only one who had "removed the mask of new plays, while the others remain not very good".

[35] Critics noted Zheng's proclivity for comedy during his stage days, with one writing in Xibao in 1918 that he was "witty but not frivolous and gimmicky, but not exploitative [with a] refined difference from those who just want to mess around.

In Havoc in a Bizarre Theatre, Zheng's chef character is a fan of cinematic comedy who distractedly serves live animals to patrons then, when fired, replaces a sugar thief's prize with gravel.

[39] The character also made allusions to Buster Keaton, with the film historian Dong Xinyu likening his pushing of a street thug into hot water to a gag in The Haunted House (1921).