[2][3] Xu was born in Xiao County, Jiangsu (now part of Anhui province), with a scholar family background.

In 1918 Xu founded the Anfu Club, the political arm of the Anhui clique, which then won three-fourths of the seats in the National Assembly.

In 1919 Xu assumed command of the Northwest Frontier Defense Army, which invaded newly independent Outer Mongolia in October.

[4] In 1920, after Duan fell from power, Xu lost his position and moved his forces back to confront his enemies.

In the early 1920s, Xu was sent to Italy as part of a Chinese diplomatic mission; a secondary purpose was to get him out of the country.

In December 1925, while traveling from Beijing to Shanghai by train, Xu was kidnapped by Zhang Zhijiang, a member of Feng Yuxiang's forces.