It is not known when Xiahou Zi was born. His family was from Qiao and claimed ancestry from the Spring and Autumn period state Qi, but little is known about his traceable ancestry except for his father Xiahou Shenfeng, who served as a supervisory official at the ministry of rites. Xiahou Zi had at least two older brothers, Xiahou Min and Xiahou Jing, and at least two younger brothers, Xiahou Fei and Xiahou Ao. Xiahou Zi passed the imperial examinations in the Jinshi class in 826, during the reign of Emperor Jingzong. He subsequently served on staffs of various regional governors, before later successively serving as the prefect of Wu Prefecture and the prefect of Jiang Prefecture. He was later recalled to the capital Chang'an to serve as an advisory official with the title Jianyi Daifu, and later as an imperial attendant. In 856, by which time Emperor Jingzong's uncle Emperor Xuānzong was emperor, Xiahou was made the deputy minister of justice. In 857, he made Shangshu You Cheng, one of the secretaries general of the executive bureau of government, and given the honorific title of Shang Zhuguo. Soon thereafter, he was also made the deputy minister of census and the director of taxation — after Emperor Xuānzong had initially offered the position to the mayor of Jingzhao Municipality, Wei Ao but Wei declined.
First chancellorship
In 858, by which time Xiahou Zi was referred to as the deputy minister of defense and the director of the salt and iron monopolies, Emperor Xuānzong gave Xiahou the designation Tong Zhongshu Menxia Pingzhangshi, making him a chancellor de facto. After Emperor Xuānzong died in 859 and was succeeded by his son Emperor Yizong, Emperor Yizong continued to have Xiahou serve as chancellor, and made him Menxia Shilang, the deputy head of the examination bureau of government ; he also created Xiahou the Marquess of Qiao. In 860, when agrarian rebel Qiu Fu overran Zhedong Circuit, it was at Xiahou's recommendation that Emperor Yizong commissioned the general Wang Shi to suppress Qiu's rebellion, and it was said that it was with Xiahou's full support that Wang was fully supplied and was able to defeat Qiu. In late 860, after the end of the Qiu rebellion, Xiahou was made the military governor of Xichuan Circuit, continuing to keep the Tong Zhongshu Menxia Pingzhangshi title as an honorary title.
Second chancellorship
In 862, by which time Xiahou Zi was referred to as the former military governor of Xichuan, he was made Zuo Pushe, one of the heads of the executive bureau, and chancellor again, with the designation Tong Zhongshu Menxia Pingzhangshi. It was at Xiahou's recommendation that, in 864, the general Gao Pian was commissioned to recapture Annan from Dali forces. Late in 864, Xiahou was again removed from his chancellor position and made the military governor of Hezhong Circuit.
After second chancellorship
In 868, when Xiahou Zi was apparently still governing Hezhong, and by which time he was referred to by the title of Duke of Qiao Commandery, Dali forces made a major incursion into Xichuan Circuit. Emperor Yizong, blaming Xiahou for not having fortified Xichuan's defenses while governing Xichuan, issued an edict rebuking Xiahou and relieving Xiahou from his post as military governor of Hezhong. Xiahou was made an advisor to the Crown Prince, with his office at the eastern capital Luoyang. It was said that Xiahou died soon thereafter, but the date is not known.
