Born in Matsuyama, Ehime Prefecture, he was an AFS exchange student in high school, graduated with a liberal arts degree from the University of Tokyo and attended the John F. Kennedy School of Government at Harvard University.

[1] He spent three years working at the Economic Planning Agency (of which his father, Jun Shiozaki, was then director)[citation needed] and at the Bank of Japan.

Following his father's resignation, he ran for the Diet in 1993 and was elected to represent the first district of Ehime.

[4] His appointment as Minister of Health, Labor and Welfare in the second Abe administration was announced on September 3, 2014.

[9] In July 2022, he was awarded as Honorary Member of the Order of the British Empire (MBE), for services to UK/Japan relations.