After returning to China in 1926, Wu began a career in government service, first as a tax collector in Hankou, today part of Wuhan, for the local warlord Xia Douyin.

When the Yangtze River appeared ready to flood in 1936, Wu oversaw the construction of a huge dike system which saved the city.

[3] With the fall of Hankou to Japanese forces in October 1938 during the Second Sino-Japanese War, Wu and his family fled to Chongqing.

He served as vice minister of Foreign Affairs from 1943 to 1945, interacting with Zhou Enlai as part of the united front against the Japanese.

Wu attempted to bring a greater degree of self-governance to the Taiwanese people, allowing for the election of certain local officials by popular vote.

Wu was opposed by many conservative members of the Nationalist government, including Chiang Ching-kuo and Chen Cheng.

That same year, Wu wrote an article in Look magazine entitled "Your Money is Building a Police State in Taiwan".

[6] The war of words between Wu and Chiang's regime escalated further, including a resolution against him by the ROC's National Assembly.