晋出帝
Upon taking the throne, Shi Chonggui took a hardline position in relations with Khitan — refusing to subjugate Later Jin to Khitan, like Emperor Gaozu did. As a result, war began between the two states. In 944, during a major Khitan incursion (which, for some time, captured and held Yedu) to aid Yang (who had rebelled at Tianping Circuit), Gao was put in titular charge of the overall operations, but it was said that Shi Chonggui's trusted general Jing Yanguang, the commander of the imperial guards, was actually the one giving orders, causing the other generals to be displeased. During one of the battles, Khitan forces had Gao, Fu Yanqing, and Shi Gongba () under siege at Qicheng (戚城, in modern Puyang, Henan). The city almost fell, and Jing did not come to its aid, but when three generals' request for emergency assistance reached Shi Chonggui, Shi Chonggui himself went to the city's rescue and lifted the siege. Shortly after this battle, Shi Chonggui relieved Jing of his post as the commanding general of the imperial guards, putting Gao in that position instead.