Izumi Mizumori joined the Ministry of Finance in 1969 and occupied a number of positions, including: Secretary to the Japanese Embassy in Singapore, Commissioner of the Sendai Regional Taxation Bureau and Director General of the Printing Bureau. Mizumori resigned from the Ministry and became Director of TEITO Rapid Transit Authority in 1998.

Mizumori joined ORIX Life Insurance Corporation in June 2001 as an Advisor. He then became Vice President in July 2001, before assuming the role of President and Group Corporate Executive Officer in October of the same year. Mizumori became a Group Executive under a "Company with Committees" structure in June 2003. In August 2007, he became a Group Senior Vice President.

Mizumori was born in 1945.