During Li Cunxu's reign In 923, Li Cunxu declared himself emperor of a new state called the
Later Tang. He subsequently carried out a campaign that destroyed Later Liang later in the year—a campaign in wherein Li Siyuan played a prominent role. Shi Jingtang and Li Congke both had battlefield accomplishments during the campaign, but Shi did not receive prominent honors as his contributions were not well-known. According to traditional accounts, it was because he did not like to brag about them. However, Li Siyuan was aware of his contributions. Before Li Siyuan's and Li Cunxu's armies could engage each other, however, Li Cunxu was killed in a mutiny at Luoyang itself. Li Siyuan subsequently entered the city and claimed the title of regent.
During Li Siyuan's reign Li Siyuan appeared to be initially hesitant to take the throne himself, as at that time, Li Cunxu's son
Li Jiji the Prince of Wei, who had been the commander of the army that destroyed Former Shu, was returning from the Shu lands and heading toward Luoyang with his army, and he initially signaled support for Li Jiji. However, after apparently concluding that he would not be tolerated if Li Jiji became emperor, he sent Shi Jingtang and Li Congke to take up defensive positions at Shan Prefecture (陝州, in modern
Sanmenxia,
Henan) and Hezhong Municipality (河中, in modern
Yuncheng,
Shanxi) respectively, to block Li Jiji. Li Jiji's own soldiers began to desert, and he committed suicide. Li Jiji's subordinate
Ren Huan took over command of the remaining army and rendezvoused with Shi, signaling support for Li Siyuan. With Li Jiji dead, Li Siyuan claimed the throne. In 930, the two main military governors of the Shu lands, both commissioned by Li Cunxu before his death—
Meng Zhixiang the military governor of Xichuan Circuit (西川 headquartered in modern
Chengdu,
Sichuan) and
Dong Zhang the military governor of Dongchuan Circuit (東川 headquartered in modern
Mianyang,
Sichuan)—fearing that Li Siyuan's powerful chief of staff
An Chonghui was intending to act against them, rebelled together. Li Siyuan sent Shi to command the army against the two circuits—a commission that Shi accepted despite his misgivings about the campaign. Shi quickly advanced to
Jianmen Pass, but, after capturing it, could not advance further easily against the Dongchuan and Xichuan armies. When Li Siyuan subsequently sent An to the front to monitor the campaign, Shi took the opportunity to write to Li Siyuan, explaining his misgivings from the campaign, and Li Siyuan began to be convinced. Li Siyuan subsequently forced An into retirement and then killed An, and then recalled Shi's army (although Shi already began to retreat before receiving the retreat orders). Li Siyuan subsequently again made him the deputy commander of the imperial guards (by this point, serving as the deputy to another biological son of Li Siyuan's,
Li Congrong the Prince of Qin). He was also given the military governorship of Heyang Circuit (河陽, headquartered in modern
Jiaozuo,
Henan). Li Siyuan became deathly ill in late 933. Li Congrong, believing that Li Siyuan's chiefs of staff
Zhu Hongzhao and
Feng Yun would try to divert the succession away from him, decided to try to forcibly take power, but his army was defeated by the imperial guards, and he was killed. In the aftermaths, Li Siyuan summoned Li Conghou back from Tianxiong (where Li Conghou was serving as military governor), but died before Li Conghou arrived at Luoyang. Li Conghou subsequently arrived and took the throne. After Shi's return to Hedong, there were repeated incursions of Later Tang's northern circuits by Later Tang's northern rival
Khitan Empire. Both Shi and Zhao Dejun repeatedly requested reinforcements, and they were allowed to amass troops and supplies at their circuits. As Shi was still apprehensive that Li Congke might be suspicious of him, Shi maintained an information network at Luoyang to keep himself informed of the emperor's actions—the network included two of Shi's own sons, who served in the imperial guards (whose names were variously recorded, and one of whom might have been a brother whom he adopted as a son), and the servants of Empress Dowager Cao. and in the
Zizhi Tongjian as Shi Chongyin () and Shi Chongyi ().) In 935, there was an incident in which, when the imperial envoy was at the front to review Shi's army and to deliver the imperially-bestowed supplies to the army, the soldiers began to chant, "May you live 10,000 years!" at Shi—a chant that should be reserved for the emperor. Shi became fearful, and under the advice of his staff member Duan Xiyao (), had Liu Zhiyuan behead 36 of the soldiers leading the chant, to try to alleviate the suspicion might be cast on him, but that did not stop Li Congke from suspecting him of having greater ambitions upon receiving the report from the imperial envoy. As Shi was formally the commander of the army to the north, Li Congke commissioned the general
Zhang Jingda to serve as his deputy to divide his command. == Rebellion against Li Congke ==