Because of Tan's interest in the Chinese community's affairs as well as national reforms in China, he could not help but be embroiled in the politics of the day. In fact, he was a key player in the Chinese revolution to overthrow the Qing Manchurian imperial rulers to restore Han democratic leadership. Tan's revolutionary fervour started at a young age. He joined the Tong Meng Hui to further his vision of a republican China.

After the success of the revolution, Tan did not relent in his efforts to build a strong China. He knew that the work of the Chinese revolution had just begun with the overthrow of the Qing authorities. To maintain law and order in Fukien in the heady days following the 1911 revolution, Tan raised a sum of S$120,000 to hire law enforcement personnel.

In Singapore, Tan was an accomplished debater in Parliament. He was consistently outspoken on community affairs. Being critical of the proposed Income Tax Bill in 1916 in the council, he debated eloquently and firmly against it, even rallying support from business organizations like Singapore Chinese Chamber of Commerce. He argued so convincingly during an extraordinary meeting in the Chamber that 181 out of 184 members supported his cause against the Bill. Such unity was rarely seen considering the fact that the Chamber had diverse interests and was an umbrella outfit for different, sometimes antagonistic, dialect groups.

In 1938, he was elected as the Chairman of the Federation of China Relief Fund of the South Seas, a post to which he was re-elected two years later. Tan's prestige in Southeast Asia was demonstrated when he was elected by 168 Chinese representatives from various areas in Southeast Asia to coordinate the fund-raising campaigns in Southeast Asia.