Stephen Turnbull took his first degree at Cambridge and has two MAs (in Theology and Military History) from Leeds University. In 1996 he received a PhD from Leeds for his thesis on Japan's 'Hidden Christians'. In its published form the work won the Japan Festival Literary Award in 1998.

Having lectured widely in East Asian Studies and Theology he is now retired and holds the honorary positions of Lecturer Emeritus at Leeds University, Research Associate at SOAS and Visiting Professor of Japanese Studies at Akita International University.

His expertise, including an extensive picture library, has helped with numerous media projects including the award-winning computer strategy game Shogun Total War, and in 2010 he acted as Historical Adviser to Universal Pictures for the movie 47 Ronin.