Gu Zhongchen was born in Wuxi, Jiangsu. By the end of the Qing dynasty, he was Commandant of the Anhui Military Academy. However, a number of his cadets, including Bai Wenwei (柏文蔚), entered the pro-republican Tongmenghui movement, so he came under suspicion by imperial authorities and was demoted to a trifling job in Nanjing. During the Xinhai Revolution of 1911 that overthrew the Qing dynasty, Gu Zhongchen participated with the Tongmenghui as the General Councilor of the Jiangsu–Zhejiang United Army. In May 1924, he was appointed to the Commander of the 4th Army of the Northern Expedition Force commanded by Sun Yat-sen.