Xu"s ancestral hometown was Yinxian County (current Yinzhou District), Ningbo, Zhejiang Province. He was at one time the Viceroy of the Three Northeast Provinces and at the end of the Qing dynasty he was made chief of the general staff despite being a civilian. He resigned as secretary of state (premier) in protest to Yuan"s imperial ambition in late 1915.
His election as president was largely engineered by Duan Qirui and his Anhui clique.
He was chosen because he was a civilian yet had close ties to the Beiyang Army and was neutral to both its Zhili and Anhui cliques. Lacking any military power of his own, he had to play Duan, Zhili leader Cao Kun, and Fengtian leader Zhang Zuolin against each other to stay in power.
He held a massive celebration in Beijing for China"s victory in World War I on 18 November 1918, however he brought troops into the Allied intervention in the Russian Civil War. A ceasefire with Sun Yatsen"s rival Constitutional Protection government was declared and intellectuals were given greater freedom.
This lasted until news from France showed how Duan Qirui promised German territory in Shandong to Japan.
Large student protests (May Fourth Movement) led to Xu cracking down with mass arrests. The delegation was ordered home and China refused to sign or ratify the Versailles treaty. Consequently, the shaky alliance between the Zhili and Anhui cliques collapsed with Duan decisively defeated.
This led to the era of high warlordism.
Conflict with the south flared again in 1920 and he also failed to retake Mongolia. Cao Kun, who never liked Xu, pressured him out of office and restored Li Yuanhong.
His presidency lasted the longest during the warlord era. He was also the only non-acting president of the Beiyang government to be a civilian.