In his youth, Wang Yanzhang became a soldier under the command of the major warlord Zhu Quanzhong the military governor (Jiedushi) of Xuanwu Circuit (宣武, headquartered in modern Kaifeng, Henan), and became known for his bravery and ferocity.

[5] In 913, by which time Emperor Taizu had been assassinated by and succeeded by his son Zhu Yougui the Prince of Ying,[6] Wang Yanzhang was made the prefect of Pu Prefecture (濮州, in modern Puyang, Henan), but remained in the main Later Liang imperial army as the commander of the forces from Pu Prefecture.

Wang killed the secret messenger and refused to respond; as a result, several years later, Jin had his wife and children executed.

[1][7] In 916, Wang was promoted to be the defender (防禦使, Fangyushi) of Zheng Prefecture (鄭州, in modern Zhengzhou, Henan), but remained in the Later Liang imperial army.

[1] Around the new year 919, Wang, then under the command of He Gui, participated in a major confrontation between Later Liang and Jin forces at Huliu Slope (胡柳陂, in modern Heze, Shandong).

[8] In 919, Wang was made the acting military governor of Kuangguo Circuit (匡國, headquartered in modern Xuchang, Henan), but continued to serve as a general in the imperial army.

Shortly after, he had his general Li Siyuan launch a surprise attack across the Yellow River on Later Liang's Tianping Circuit (天平, headquartered in modern Tai'an, Shandong), capturing it.

[2] After being commissioned, Wang immediately attacked the Later Tang-held city of Desheng (德勝, in modern Puyang)—which was divided into two parts by the Yellow River.

He had long resented what he saw as the corrupting influence that Zhu Zhen's brother-in-law Zhao Yan and four brothers/cousins of Zhu Zhen's deceased wife Consort Zhang (including Zhang Hanjie, who was her brother), and had told people, "After I victoriously return, I will kill all the wicked men on the behalf of the people of the empire."

After his forced withdrawal from Majiakou, Zhu Zhen believed the false accusations against Wang and relieved him of his command of the main Later Liang army, instead ordering him to rendezvous with Dong Zhang to attack Ze Prefecture (澤州, in modern Jincheng, Shanxi).

The Later Tang emperor decided to risk opening up his rear by heading immediately to Yun to rendezvous with Li Siyuan, bypassing the Later Liang main army, and attack Daliang directly.

[2] Just as the Later Liang army was about to put the four-prong plan into effect, the Later Tang emperor arrived at Yun Prefecture and advanced toward Daliang, with Li Siyuan as his forward commander.

They encountered and surprised Wang, who was forced to retreat to the poorly-fortified city of Zhongdu (中都, in modern Jining, Shandong).