長崎大学
From 1984 to 2007, Niikawa was Professor and Chairman of the Department of Human Genetics at Nagasaki University School of Medicine. He led several medical students and researchers, including Naomichi Matsumoto. After retiring from the position in Nagasaki and becoming Professor Emeritus in 2007, he became Professor and Director at the Research Institute of Personalized Health Sciences, Health Sciences University of Hokkaido, where he served as President of the University from 2010 to 2016.