After Dou was defeated and captured by the Tang general Li Shimin (the later Emperor Taizong), Wang surrendered.

Wang Shichong's ancestors were surnamed Zhi (支), originally from the Western Regions (Xiyu) and were not ethnic Han Chinese.

Wang Shou later served as a secretary to the governor of Bian Province (汴州, roughly modern Kaifeng, Henan).

It was said that he was skillful in his application of laws and use of language, such that even when he made suggestions that did not appear to make sense logically, people were unable to refute him.

In the fall of 615, Emperor Yang, Empress Xiao, and much of the Sui court was touring Yanmen Commandery on the northern frontier when it received word from the Chinese princess Yicheng that her husband, Shibi Khan, was launching a surprise attack on the area.

Because the siege was lifted largely through the treacherous deception of Princess Yicheng, who told her husband that the khaganate had come under attack from the north in his absence, Emperor Yang followed the advice of councilors like Su Wei and gave no rewards and few promotions to the soldiers who had come to his assistance, causing great resentment among the military.

Hearing of Wang's great personal distress, however, the emperor believed in his loyalty and promoted him to acting governor of Jiangdu in 616.

They were under the command of Xue Shixiong (薛世雄), who was ordered to take his forces from Zhuo Commandery (涿郡, roughly modern Beijing) to Luoyang was well.

However, Xue was intercepted and defeated by Dou Jiande and forced to return to Zhuo Commandery, and died there, leaving the other generals without a central commander.

For the next several months, he battled with Li, and while each had victories, the results were generally indecisive, although Wang's forces took the brunt of the losses.

Wang was made one of the heads of the examination bureau (門下省, Menxia Sheng) and created the Duke of Zheng.

He and six other officials, Duan Da (段達), Yuan Wendu (元文都), Huangfu Wuyi (皇甫無逸), Lu Chu (盧楚), Guo Wenyi (郭文懿), and Zhao Changwen (趙長文), formed a collective leadership and were known as the "seven nobles."

Li was subsequently able to repel Yuwen's attacks, and when the news reached Luoyang, the officials were largely pleased—but Wang was not, stating, "Why are they giving offices and titles to a bandit?"

Upon hearing of Yuan Wendu's and Lu Chu's deaths, Li Mi broke off of peaceful relations with Yang Tong's regime.

Against his initial judgment, Li was persuaded by his secretary Bing Yuanzhen (邴元真), who could benefit from the transactions, to trade food to Wang for clothes.

The major rebel leader Dou Jiande, who had claimed the title of Prince of Xia, also nominally submitted to Yang Tong.

Wang was given the honorific office of Taiwei (太尉), and he began to gather officials with good reputations onto his staff.

In late spring 619, Wang had Yang Tong create him the Prince of Zheng and grant him the nine bestowments—both ultimate steps before taking the throne.

In fall 620, Tang's Emperor Gaozu commissioned his son Li Shimin the Prince of Qin with an army to attack Luoyang, and Wang Shichong prepared his own forces to defend and counter.

By winter 620, Zheng was in a desperate situation, and Wang Shichong sent messengers to Dou, seeking help from Xia forces.

Upon hearing that Dou was approaching, he decided to advance east to take up defensive position at the key Hulao Pass in advance of Dou's arrival, leaving a relatively small Tang army, under the command of his brother Li Yuanji the Prince of Qi, at Luoyang.

Meanwhile, Dou, against the advice of his strategist Ling Jing (凌敬) and his wife Empress Cao, advanced to Hulao in summer 621.

He considered fighting his way out of the siege and fleeing to Xiangyang, defended by his nephew Wang Honglie (王弘烈) the Prince of Wei.

Li Shimin took Wang Shichong and Dou Jiande back to the Tang capital Chang'an to present them to his father Emperor Gaozu.

In fall 621, Emperor Gaozu spared him but demoted him to commoner rank, exiling him and his clan to modern Sichuan, while executing Dou.

Emperor Gaozu only punished Dugu by removing him from his post as the prefect of Ding Prefecture (定州, roughly modern Baoding, Hebei).

The Later Jin historian Liu Xu, the lead editor of the Old Book of Tang, commented:[11] Wang Shichong was a wicked man who happened to encounter an incompetent ruler.