The son of Takejiro and Hiroko Hanno Ijiri was born on February 24, 1935 in Kobe, Japan. He developed an interest in math at an early age. When he was six, he attended abacus school and when he was in the tenth grade his father, a baker, asked him to do his accounting. He enjoyed it and decided to become a CPA. In 1952, shortly before graduating from Nara High School of Commerce, he passed an exam that enabled him to take the CPA exam without a college degree. Continuing his study at night at Doshisha Junior College in Kyoto, he passed the CPA exam in 1953. While meeting the three-year practice requirement, he attended Ritsumeikan University in Kyoto and received a bachelor of law degree in 1953. Also in this year, at the age of 21, he completed all requirements for the CPA certificate, still the youngest ever on record in Japan.
After graduation, he was a practitioner for three years in Tokyo, first with a small firm, then with Price Waterhouse & Co. He left Price Waterhouse in 1959 to attend graduate school in the United States at the University of Minnesota, where he received a master's degree in 1960. In this year, he also became a member of Beta Alpha Psi. He then attended Carnegie Mellon University, where he received a doctor's degree in 1963.
He was on the faculty of Stanford University during the period 1963-67, serving as an assistant (1963-65) and an associate (1965-67) professor. He returned to Carnegie-Mellon in 1967 as a full professor. In 1975 he was named the Robert M. Trueblood Professor of Accounting and Economics, a title he held until 1987 when he was promoted to Robert M. Trueblood University Professor of Accounting and Economics; a university professorship is the highest honor his university bestows on a faculty member.
He has been active in professional organizations. A member of the AAA since 1963, he has served on numerous committees and offices of the Association including president (1982-83) and vice president (1974-75). He has been a consultant to a number of business and nonprofit organizations.
He has written over 100 articles for professional journals, and he has authored a number of monographs and books including The Foundations of Accounting Measurement - A Mathematical, Economic, and Behavioral Inquiry (1967), Theory of Accounting Measurement (1975), Skew Distributions and the Sizes of Business Firms with Herbert A. Simon (1977), Recognition of Contractual Rights and Obligations: An Exploratory Study of Conceptual Issues (1980), Historical Cost Accounting and Its Rationality (1981), Accounting Structured in APL (1984), and Momentum Accounting and Triple-Entry Bookkeeping (1989). He and William W. Cooper edited in 1983 the sixth edition of Kohler's Dictionary for Accountants after the death of the author and Hall of Fame member Eric L. Kohler. Several of ljiri's books have been translated into Japanese, and some into French and Spanish.
As an outstanding accounting teacher and researcher, he has received many honors. He is the only four-time recipient of the AICPA-AAA's Notable Contributions to Accounting Lecturer Award (1966, 1967, 1971, 1976). In 1985 he was selected as the AAA's Distinguished International Lecturer and in 1986 he received that organization's Outstanding Accounting Educator Award.
He married Tomoko Nishimura on June 17, 1962; they have two children. In his leisure time he enjoys puzzles, haiku, and computers.