Shibukawa Mitsuyori was born in 1372. He was the son of Yoshiyuki.
In 1395, he replaced Ryoshun Imagawa as Chinzei Tendai (military commissioner in Kyushu) when Ryoshun was discharged by the Ashikaga Shogunate due to his inability to suppress feuds among the Otomo, Shoni and Shimazu families which were influential in Kyushu. Mitsuyori, however, was less competent than Ryoshun and the prestige of Chinzei Tandai waned. He sent envoys to Korea and conducted trade with that country.