He is a former career bureaucrat in the Ministry of Internal Affairs and Communications[1] (briefly serving as Director of the CLAIR London Office) and graduate of University of Tokyo.

[1] In 2016 Mutai was appointed Parliamentary Vice Minister for Reconstruction and shortly after hit global headlines concerning an incident concerning a ministerial visit to a disaster-hit region.

[2] Half year later at a campaign party Mutai joked about the incident only to be criticized by Chief Cabinet Secretary Yoshihide Suga.

[3] At the 2017 general election Mutai was defeated in his Nagano constituency but re-elected to the Diet under his party's proportional representation bloc.

[4] He was reappointed to government as a State Minister for the Environment in October 2021 [5] but relieved of his position in the August 2022 Kishida reshuffle [6].