Sun returned to China in 1906 and became chief secretary of the Grand Council, which was tasked with reorganizing the country's administrative system.

In 1910, he urged the imperial authorities that a cabinet system be established, and in 1911 he recognized the independence of Shandong from Manchu rule.

Sun served as minister of foreign affairs until January 1915, until he resigned in protest of Japan's Twenty-One Demands.

In January 1924, Sun briefly became premier a second time, but resigned in July after friction with finance minister Wang Komin.

After stepping down, Sun became chairman of the foreign affairs committee and refused several other postings before becoming president of the Hanyeping iron and steel complex and the China Merchants' Steam Navigation Company.