Prior to joining Aum, Hayashi was a senior medical doctor with "an active 'front-line' track record" at the Japanese Ministry of Science and Technology (now a part of the Ministry of Education, Culture, Sports, Science and Technology, or MEXT in short). Himself the son of a doctor, Hayashi graduated from Keio University, one of Tokyo's top universities. He was a heart and artery specialist at Keio Hospital, which he left to become head of Circulatory Medicine at the National Sanitorium Hospital in Tokai, Ibaraki (north of Tokyo). Somewhere along the line Hayashi became disillusioned and decided to look beyond conventional medicine. He found AUM during his search.