The younger son of King Daoxiang and Queen Daochang, King Youmiu was nevertheless able to succeed to the Zhao throne before his elder brother Zhao Jia due to his mother Chang Hou's intervention.
He inherited a country that was in danger of being conquered by the Qin state, as it had been since a defeat at the Battle of Changping in 260 BCE.
The state of Zhao, however, was able to survive thanks to the services of General Li Mu, who successfully repelled Qin attempts at exploiting the situation.
The Qin devised a scheme to get rid of him; through bribing a close confidante of King Youmiu, the courtier Guo Kai (郭開), Li Mu was arrested and executed on suspicion of treason.
In 228 BCE, Qin forces under the leadership of Wang Jian captured the Zhao capital of Handan.