Fumio Inagaki is a geomicrobiologist, Principal Senior Scientist, and Director of the Mantle Drilling Promotion Office, Institute for Marine-Earth Exploration and Engineering (MarE3), Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and a Professor at the Graduate School of Sciences, Tohoku University, Japan. He earned his Ph.D. at the Kyushu University, Japan (2000), under the supervision of Prof. Seiya Ogata in studying thermophilic microbial communities associated with silicate mineralization at geothermal power plants. Then, he joined as a researcher at the Deep-Sea Frontier Research Program of JAMSTEC, under the supervision of Prof. Koki Horikoshi. His research interests are geomicrobiology and biogeochemistry of the ocean, with a particular focus on the deep subseafloor biosphere. He used scientific ocean drilling and state-of-the-art transdisciplinary approaches to explore the nature and limits of deep microbial life, ecosystem functionality in biogeochemical carbon cycles, co-evolution of life and Earth, and planetary habitability on Earth and beyond. He was a shipboard microbiologist of the first deep biosphere-dedicated scientific ocean drilling with the US drilling research vessel JOIDES Resolution, Ocean Drilling Program (ODP) Leg 201 at the eastern equatorial Pacific and off Peru in 2002. He first isolated two novel mesophilic chemolithoautotrophic epsilon-proteobacteria (Sulfrimonas autotrophica gen. nov., sp. nov. 2003, and Sulfurovum lithotrophicum gen. nov., sp. nov. 2004) from the Okinawa Trough hydrothermal fields, which isolates were appeared to be the abundant, ecologically significant sulfur and/or hydrogen-metabolizing bacteria globally distributed at cold seeps and deep-sea hydrothermal environments. He was a research fellow of the Alexander von Humboldt Foundation at the Max Planck Institute for Marine Microbiology in Bremen, Germany, under the supervision of Prof. Bo Barker Jørgensen (MPI-MM: 2005-2006). Going back to Japan, he served as the Deputy Director of Kochi Institute for Core Sample Research (KCC: 2015-2019) and the Research and Development Center for Ocean Drilling Science (ODS: 2016-2019) in JAMSTEC. As of today, he has participated in 28 scientific research cruises, in which he served as (co-)chief scientist for 15 expeditions, including 3 co-chief expeditions; Integrated Ocean Drilling Program (IODP) Expeditions 329, 337, and International Ocean Discovery Program (IODP) Expedition 370. With these international collaboration activities on multidisciplinary projects, numerous students, scientists, technicians, and ship operators have worked together on challenging missions to explore the biosphere frontiers deep beneath the ocean. In 2012, during IODP Expedition 337 using the Japanese riser-drilling research vessel Chikyu, his international team extended the world depth record of previous scientific ocean drilling down to 2,466 meters below the ocean floor, revealing the occurrence of deep subseafloor microbial communities in ~20-million-year-old coal and shale beds (Inagaki, et al., Science, 2015). His study includes the global abundance, biogeographical distribution, and diversity of subseafloor microbial communities (Archaea, Bacteria, and Eukaryote), adaptive evolution, long-term survival strategy, and limits of subseafloor life, geosphere-biosphere interactions at plate subduction zones, and planetary habitability through scientific ocean drilling down to the upper mantle (Inagaki & Taira, Oceanography, 2019). Based on his knowledge and experience in geomicrobiology and scientific ocean drilling, he and his colleagues also explore sustainability sciences for developing carbon neutral and energy systems, including carbon capture, utilization, and storage (CCUS). He published ~200 peer-reviewed international articles and book chapters and ~70 Japanese articles with more than 200 media coverages. He served as an Editorial Board member of Applied and Environmental Microbiology (2005-2016), and a Senior Editor of The ISME Journal (2017-2019), which are flagship journals in the field of environmental microbiology and microbial ecology. He was a Deep Life steering committee member of the Deep Carbon Observatory (DCO: 2013-2019). In 2015, he was the first awardee of the American Geophysical Union (AGU)-the Japanese Geoscience Union (JpGU) Asahiko Taira Scientific Ocean Drilling Research Prize (Taira Prize). His work and contribution to the scientific community were also recognized with the Cozzarelli Prize of the National Academy of Science in 2017 (Category IV), the Copernicus Medal in 2019 at the European Geophysical Union (EGU), The Japan Association for Petroleum Technology (JAPT) Special Award in 2021, Geochemistry Fellow of Geochemical Society (GS) and European Association of Geochemistry (EAG) in 2021, and the AGU Fellow in 2021. He is currently serving as an Associate Editor of Science Advances, AAAS (since 2019), and an Advisory Board member of Earth 4D: Subsurface Science & Exploration, CIFAR, Canada (since 2019). His international academic services also include being a steering committee member of the International Society of Subsurface Microbiology (ISSM, since 2017) and the Program Committee Co-chair of the JpGU-AGU Joint Meeting 2020. He is currently a Guest Professor at Waseda University and Kochi University, Japan (2020.4-present), and is a Professor at the Graduate School of Sciences, Tohoku University, Japan (2021.3-present).