Yasushi Adachi was born in Izumiotsu, Osaka Prefecture and grew up in Ibaraki, Osaka Prefecture. After graduating from Osaka Ibaraki High School, he went on to Kyoto University, where he received his Bachelor's and Master's degrees in Civil Engineering. In 1990, he joined the Ministry of International Trade and Industry (MITI). In 1998, he received his Master's degree in International Relations from Columbia University. In 2013, he retired from the Ministry after the Great East Japan Earthquake.