His father Li Shunqing (李舜卿) was the tactical officer at Shen Prefecture (深州, in modern Hengshui), which Raoyang belonged to.
It was said that he was intelligent in his youth, and was writing artful texts even when he was in his teenage years, surprising his family members.
[5] The deaths of Guo and, subsequently, his ally and fellow major general Zhu Youqian, however, spawned a number of mutinies in the Later Tang army.
He committed suicide, and the army subsequently returned to Luoyang under the command of his general Ren Huan and submitted to Li Siyuan.
After the mourning period was over, Fan Yanguang, who was then the military governor of Chengde Circuit (成德, headquartered at Zhending), made Li Song his secretary, in charge of the communications.
Li Siyuan wanted an appropriate military governor for Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi) to combat the Khitan incursions.
During a meeting at the office of the chief of staff, it was Li Song who spoke up in favor of commissioning Shi.
Li Siyuan happened to be sending emissaries to the meeting at that time to rush the decision, so Fan and Zhao acquiesced.
However, Xue opposed, and argued that the Khitan emperor would insist on having Li Congke's young daughter marry him (or his son).
Shortly after, he issued an edict moving Shi from Hedong to Tianping Circuit (天平, headquartered in modern Tai'an, Shandong).
Believing the situation to be hopeless, Li Congke committed suicide with his family, ending Later Tang.
In Li Song's case, he was made the deputy minister of defense (兵部侍郎, Bingbu Shilang) and put in charge of taxation.
However, this displeased Liu Churang (who wanted to be chief of staff) and Yang Guangyuan, who was then sieging Fan Yanguang at Tianxiong Circuit (天雄, headquartered in modern Handan, Hebei) as Fan had rebelled against Shi earlier in the year (as Sang was putting curbs on Yang's power).
Li Song was given the additional title of minister of public works (工部尚書, Gongbu Shangshu), while Liu was made chief of staff.
[10] In 941, Shi made his general Liu Zhiyuan, who was then the commander of the imperial guards, the military governor of Hedong.
One immediate question was how the Later Jin court would report this news to Emperor Taizong[12] (who had changed his state's name from Khitan to Liao by this point).
[12] By 944, Sang Weihan was again chief of staff and chancellor, and was said to control the army with discipline, enabling its effectiveness in battles against Liao.
[13] In late 945, Shi finally removed Sang as chief of staff and chancellor, making him the mayor of then-capital Kaifeng.
He spread false news that Zhao Yanshou was intending to defect to Later Jin, rumors that were believed by Feng and Li Song.
[14] After Kaifeng's fall to Liao, Shi Chonggui and his family (including Shi Jingtang's wife Empress Dowager Li) were put under house arrest by the Liao general (formerly a subordinate of Du Wei's), Zhang Yanze, whom Emperor Taizong sent as forward commander to take control of the city.
[15] Emperor Taizong made the comment, "All I gained by destroying the southern dynasty was Li Song.
Tiring of dealing with these rebellions, he decided to leave his brother-in-law Xiao Han in charge at Kaifeng, while he himself headed back to Liao's main territory.
[15] In the aftermaths of Emperor Taizong's death, Zhao wanted to seize what remained of Liao-controlled former Later Jin territory, but not wanting to yet break with Liao, he only claimed that Emperor Taizong left an edict authorizing him to oversee the southern court (i.e., the former Later Jin territory).
Unaware of this development, Zhao prepared to hold a semi-imperial ascension ceremony, in which the officials and generals would all bow to him.
Li Song, pointing out to him that it was uncertain whether the Khitan generals would agree, persuaded him not to hold the ceremony.
In the aftermaths of the battle, the city became controlled by the officer Bai Zairong (白再榮), who had the soldiers surround Li Song's and He's residences, demanding treasury.
Li Song and He surrendered all their treasure, but Bai then considered killing them to prevent reprisal later, but Li Gu talked him out of it, pointing out that the new emperor (i.e., Liu Zhiyuan, who had established Later Han and taken over the Central Plains by this point) would punish him if he frivolously killed the chancellors.
[16] After the Heng mutiny, Li Song, along with Feng Dao and He Ning, returned to Kaifeng to submit to Liu Zhiyuan.
None of them, however, was given a key position, but only honorific titles — in Li Song's case, Taizi Taifu (太子太傅).
[16] While Li Song was with the Liao army at Heng, however, Liu, apparently believing that both Feng and Li Song had turned their loyalty over to Liao, awarded their mansions at Kaifeng to his key followers (and by this point, chancellors) Su Yugui and Su Fengji, respectively.