He was the son of King Zhao and the older brother of Lord Xinling (Wei Wuji).
In 275 BC, after a Han general fled to the Wei capital Daliang, King Anxi began a war against Qin in an alliance with Qi.
Qin forces under chancellor Wei Ran and general Bai Qi captured 4 cities, besieged Daliang and killed 40,000 people.
In 273 BC, with the assistance of Lord Mengchang of Qi, he began another war in an alliance with Zhao.
In 257 BC, he assisted Zhao when its capital Handan was besieged by Qin forces, at the request of Lord Pingyuan of Zhao, who was married to Lord Xinling's older sister.