It is not known when Xiao Ye was born. His ancestry came from the imperial house ofLiang Dynasty — which in turn traced its ancestry to the great Han Dynastyprime ministerXiao He, whose ancestry was purportedly from the ruling house of the Spring and Autumn period and Warring States periodstate Song. Xiao Ye's eighth-generation ancestor was the brief-reigning Liang emperor Xiao Yuanming, a son of Xiao Yi, an older brother to Liang's founder Emperor Wu of Liang. For several generations prior to him, Xiao Ye's male-line ancestors served as officials of Tang Dynasty, including Xiao Ye's grandfather Xiao Zhi, who served as an imperial attendant, and his father Xiao Ge, who served as a prefectural prefect. Xiao Ye had at least one older brother, Xiao Jie, and one younger brother, Xiao Xian. It is known that Xiao Ye passed the imperial examinations in the Jinshi class, but it is not known when that occurred. He successively served as an imperial censor with the title Jiancha Yushi ; an imperial scholar ; and the prefect of Heng Prefecture.
During Emperor Xuānzong's reign
In the middle of the Dazhong era of Emperor Xuānzong, Xiao Ye was recalled to the capital Chang'an to again serve as imperial scholar; he then successively served as Zhongshu Sheren, a mid-level official at the legislative bureau of government ; and then the deputy minister of census, serving also as the director of taxation. As of 856, Xiao Ye was serving as the deputy minister of defense as well as the director of finances, when Emperor Xuānzong was set to make him chancellor, even readying the imperial scholars to draft an edict to that effect. However, after he delivered that direction to the imperial scholars, the eunuchs who delivered the order, Wang Guichang and Ma Gongru, asked him whether Xiao should remain as director of taxation as well — causing Emperor Xuānzong to suspect Wang and Ma of associating with Xiao. Emperor Xuānzong therefore commissioned Cui Shenyou as chancellor instead. This merely delayed Xiao's commission, however, as in 857, Xiao was nevertheless made chancellor as well, with the designation Tong Zhongshu Menxia Pingzhangshi, and also remained the director of finances briefly, although he was relieved of that responsibility late in 857. He would remain chancellor for the rest of Emperor Xuānzong's reign.
After Emperor Xuānzong's reign
Emperor Xuānzong died in 859 and was succeeded by his son Emperor Yizong. Late that year, Xiao Ye was removed from his chancellor position and made the military governor of Jingnan Circuit, continuing to carry the Tong Zhongshu Menxia Pingzhangshi title as an honorary title. He was later transferred to Xichuan Circuit, but was said to be powerless in stopping Nanzhao incursions. In 864, he was transferred to Shannan West Circuit. He later served as the military governor of Hedong Circuit, and was said to be undistinguished in his service there, before dying. His death year is not known, probably 874, before the next military governor took office.