Atsushi Komamine was one of the pioneers of plant tissue culture in Japan and a researcher with many friends throughout the world. His objective was to determine the potential capacities of plant cells, and he contributed considerably to plant tissue cultivation research by establishing several unique culture systems that controlled cell division and differentiation. He emphasized that the uniformity of cultured cells and the synchrony of the plant cell response at a high frequency were necessary to study the functions of plant cells using biochemical and molecular biological methods. He trained over 300 people, and many outstanding individuals in academia and industry emerged under his tutelage. He was an outstanding mentor: with his accommodating attitude, he was loved dearly by students and foreign researchers alike. He set up the Asia Pacific Association of Plant Tissue Culture and Agribiotechnology in 2000, and he established the international journal Plant Biotechnology Reports with Jang R. Liu in 2006, thereby contributing to Asian plant sciences. In addition to describing his achievements and activities, this article aims to paint a portrait of the man himself.