Atsushi KAJII is a professor in economics, specializing in micro-economics theory. He was born in Hiroshima and received B.A. from Hitotsubashi University in Japan, and then received Ph.D. in economics from Harvard University in 1991. He was an assistant professor at the University of Pennsylvania, an associate professor at the University of Tsukuba, a professor at Osaka University, a professor at Kyoto University, and a professor at Kwansei Gakuin University from 2019. He was the editor in chief of the Journal of Mathematical Economics for 2013-19, the chair of Asian Regional Committee of the Econometric Society for 2016-19.

Kajii's academic contributions are in the area of general equilibrium theory, game theory, and decision theory under uncertainty. He is also the author of popular economics books on game theory and innovative economic interpretation of Japanese and Chinese folklore and language, which were written in Japanese and translated into Chinese and Korean.