Mutō founded and directed a minority studies group serving the Japanese government.

Mutō replaced Michio Watanabe as Minister for Foreign Affairs.

[1] After his stint as Foreign Minister, Mutō would later hold positions at the Ministry of International Trade and Industry.

In March 1993 he was appointed an Honorary Officer of the Order of Australia, for service to Australia–Japan relations.

[2] Mutō died in a Tokyo hospital from pancreatic cancer on 4 November 2009, at age 82.