He was the son of King Xiang, whom he succeeded to the throne.
During King Zhao's reign, Wei suffered from repeated attacks by the Qin state.
In 293 BC, he made an alliance with the Han state against Qin but was defeated by the Qin general Bai Qi with the loss of 240,000 troops and five cities.
In an attempt to assist in the attack on Anyi, Qin's ally, the Song state was attacked in turn by the Qi state and defeated at Wenyi (modern-day Wen County, Henan).
After a brief alliance (285–284 BC) between the states of Yan, Qin, Han and Zhao against Qi (which was negotiated at the Eastern Zhou capital Luoyang), King Zhao broke the alliance and allied with Qi against Qin.