Dai Siyuan's biography in the History of the Five Dynasties gave no family background or birthdate for him. However, it described him as a long-time officer under Zhu Quanzhong, who would eventually found the Later Liang. It was said that during the time that he served under Zhu, he was known for his military capabilities.
During Later Liang
During Emperor Taizu's reign
After Zhu Quanzhong seized the Tang throne in 907, establishing Later Liang, Dai Siyuan, who was serving as an imperial guard general, was made the prefect of Jin Prefecture. In 908, he was again made an imperial guard general, and then was made the defender of Hua Prefecture. In 909, he returned to the imperial guards as a general there.
During Zhu Yougui's and Zhu Zhen's reigns
In 912, Emperor Taizu was assassinated by his son Zhu Yougui the Prince of Ying, who took the throne. Zhu Yougui made Dai Siyuan the military prefect of Ming Prefecture. During the subsequent reign of Zhu Yougui's younger brotherZhu Youzhen, Dai was made the acting military governor of Baoyi Circuit. In 913, he was made full military governor of Baoyi. Prior to Emperor Taizu's death, the Yan general Zhang Wanjin had killed military governor of Yan's Yichang Circuit, Liu Jiwei , and then surrendered the circuit to Later Liang. Emperor Taizu then renamed the circuit Shunhua and made Zhang its military governor, but in 913 Zhang, fearing that he was not being trusted by Later Liang, offered to give up the post and become a military governor south of the Yellow River. Zhu Zhen initially replaced Zhang with Liu Shouguang's brother Liu Shouqi, who was then a Later Liang general, but at a later point apparently replaced Liu Shouqi with Dai. In 916, after Li Cunxu, the prince of Later Liang's archrival Jin, wrested control of the powerful Tianxiong Circuit, to Shunhua's south, from Later Liang, he sent an army north to attack Shunhua. Fearing that he was being trapped, Dai abandoned Shunhua and fled back to the Later Liang capital Daliang. At a later point, Dai was made the military governor of Tianping Circuit. In 919, after then-supreme commander of Later Liang forces on the northern border with Jin, Wang Zan, was suffering defeats at the hand of Li Cunxu and Li Cunxu's generals, Zhu recalled Wang and replaced him with Dai. In 921, when Li Cunxu was dealing with the aftermaths of the assassination of his ally Wang Rong the Prince of Zhao at the hands of Wang Rong's adoptive son Zhang Wenli and opting to attack Zhang, Dai tried to take advantage by attacking the Jin frontline from the south, but was defeated by LI Cunxu's adoptive brother Li Cunshen. However, in 922, he was successful in defeating and capturing another adoptive brother of Li Cunxu's, Li Cunru the prefect of Wei Prefecture, as well as the cities in the region. It was said that it dealt the Jin army a heavy loss and reversed a trend of falling morale for the Later Liang army. However, during his campaigns, Dai left the defense of Tianping's capital Yun Prefecture in the hands of his officers Lu Shunmi, Liu Suiyan, and Yan Yong. In summer 923 — shortly after Li Cunxu declared himself the emperor of a new Later Tang, Lu defected to Later Tang and revealed to the Later Tang emperor that Yun was being defended by less than 1,000 soldiers and that neither Liu nor Yan was supported well by the soldiers. The Later Tang emperor commissioned his adoptive brother Li Siyuan to launch a surprise attack on Yun, capturing it. In light of Yun falling to the Later Tang forces, which Zhu Zhen believed Dai was responsible for, he stripped the supreme commander role from Dai and demoted him to be the acting military governor of Xuanhua Circuit.
During Later Tang
Later in the year, after Later Tang's Emperor Zhuangzong captured Daliang and Zhu Zhen committed suicide, ending Later Liang, Dai Siyuan went from Xuanhua's capital Deng Prefecture to Daliang to show submission to the new emperor. Emperor Zhuangzong returned him to Xuanhua. After Emperor Zhuangzong himself was killed in a mutiny in 926 and succeeded by Li Siyuan, Dai was made the military governor of Wuding Circuit. After Meng Zhixiang the military governor of Xichuan Circuit and Dong Zhang the military governor of Dongchuan Circuit jointly rebelled against Emperor Mingzong in 930, Dai, as he was a friend of Dong's, wanted to avoid suspicion, so he asked to give up his command. Emperor Mingzong summoned him back to then-capital Luoyang to serve in the imperial guards, and later had him retire because of old age. He died in 935, during the reign of Emperor Mingzong's adoptive son Li Congke.
