The post was initially created in 1185, by Minamoto no Yoritomo, in order to aid the capture of Yoshitsune, with the additional motivation of extending the rule of the shogunate government throughout Japan. The shugo progressively supplanted the existing kokushi, who were appointed by the Imperial Court in Kyoto. Officially, the gokenin in each province were supposed to serve the shugo, but in practice, the relationship between them was fragile, as the gokenin were vassals of the shogun as well.
Shugo often stayed for long periods in the capital, far from their province, and were sometimes appointed shugo for several provinces at the same time. In such cases, a delegate shugo, or shugodai (守護代), was appointed.
Over time, the powers of some shugo grew considerably. Around the time of the Ōnin War (1467-1477), conflicts between shugo became common. Some shugo lost their powers to subordinates such as the shugodai, while others strengthened their grip on their territories. As a result, at the end of the 15th century, the beginning of the Sengoku period, the power in the country was divided amongst lords of various kinds (shugo, shugodai, and others), who came to be called daimyō.