His grandfather Wu Kexin (吳可信) was a county magistrate during Tang, and his father Wu Yue (吳蛻) passed the Tang imperial examinations in the Jinshi class during Emperor Zhaozong's Dashun era (890-891).
After passing the imperial examinations, Wu Yue was made the secretary general of Zhendong Circuit (鎮東, headquartered in modern Shaoxing), then under the control of the warlord Qian Liu.
[1][2] In 907, the Tang throne was seized by the major warlord Zhu Quanzhong, who established a new state of Later Liang as its emperor.
He summoned Wu, along with two other sons of prominent officials, Meng Can (孟粲) and Yu Bao (于葆), to his presence.
[1] In 950, Cha Wenhui (查文徽), a general of Wuyue's western neighbor Southern Tang who was serving as Southern Tang's acting military governor of Yong'an Circuit (永安, headquartered in modern Nanping, Fujian), mistakenly believed that Wuyue had abandoned Fu Prefecture and that he could take it over.
[7] Later, Qian Hongchu recalled Wu to Qiantang and again made him chancellor, serving alongside Yuan Dezhao.
The army officer Chen Man (陳滿) argued to Wu that Southern Tang was in shock over the Later Zhou invasion and that its important city Chang Prefecture (常州, in modern Changzhou, Jiangsu) would be defenseless and could easily be taken; subsequently, Chen falsely informed Wu that the Later Zhou emperor had already ordered Wuyue to attack.
The Southern Tang military prefect of Chang, Zhao Renze (趙仁澤), was captured by Wuyue forces and delivered to Qiantang.
When Chai then launched a surprise attack on the Wuyue camp, Luo did not engage fully and allowed the Southern Tang army to head toward Wu's headquarters.