Before taking up his current post in Cambridge, Thomas was trained in the Japanese Tōyōshi 東洋史 tradition, completing his BA at Aichi University (the successor to the Shanghai-based Toā Dōbun Shoin 東亜同文書院) and his MA at the University of Tokyo. In 2016, he began his PhD at the University of Tokyo as a Japan Society for the Promotion of Science DC Research Fellow under the guidance of Professors Murata Yūjirō 村田雄二郎 and Kawashima Shin 川島真. In 2019, he moved to the University of Oxford to complete his doctoral work under the supervision of Professor Henrietta Harrison. He has also studied at Nankai University in Tianjin, China, and at National Taiwan University in Taipei.