Mitani entered the Kawasaki Steel Corporation (now the JFE Steel Corporation) after graduating from the Department of Mechanical Engineering at the University of Tokyo.
He also has earned master’s degrees from the University of California, Berkeley and Stanford University.
He then joined the Boston Consulting Group. After taking posts as the Regional President for North Asia at GE Aviation Systems, the President of GE Healthcare Japan and CEO of Novartis Pharma K.K., he established Office Mitani. He took the position as Chairman of Plantec Consulting Inc. in 2016.
He joined the faculty at Shizenkan University in 2019. Mitani is also a part-time lecturer at GSDM and the School of Engineering at the University of Tokyo. Assumed Senior advisor of Boston Consulting Group(BCG) in 2019.