FAS Dean Hopi Hoekstra has named David Johnston the next Dean of Science. Johnston, who had served as interim Dean since January 2026, has spent two decades as a research scientist who reconstructs ancient ecosystems and their environmental contexts. He studies the evolution of microorganisms and their relationships to the oceans and atmosphere. With techniques such as isotope geochemistry, theoretical models, and experiments with modern microbes, his team examines how the biosphere and chemical cycles have changed throughout our planet’s history. Johnston received a BS in Environmental Studies and Philosophy from Bates College in 2002 and Ph.D. in Geology from the University of Maryland, College Park in 2007 where he worked on developing novel stable isotope systems with James Farquhar. 

Johnston moved to Harvard as a Microbial Sciences Institute Fellow from 2007-2009 blending field geology and redox geochemistry (with Andy Knoll in EPS and OEB) with microbial physiology and experimental microbiology (with Pete Girguis in OEB).  Johnston joined the EPS Faculty in 2009 and was promoted to Full Professor in 2016. Johnston served nearly 15 years as co-director of Graduate Studies in Earth and Planetary Sciences, has sat on numerous department committee, and also served on the Dean of Science’s Faculty Advisory Committee and Executive Committee. He is currently the president of the Geobiology Society, a scientific organization that unites researchers from various disciplines.

In her announcement to the community, Dean Hoekstra hailed Johnston’s record as a dependable leader and credited his “intellectual breadth, creativity, and collaborative approach" and that "as Dean of Science, David will draw on his experience and perspective to provide steady, strategic leadership to the Division, supporting our faculty in pushing the frontiers of knowledge, championing our students’ educational and research opportunities, and deepening collaborations across disciplines. His example as a leader, scientist, and mentor will be a tremendous asset to the FAS as we confront these challenges and make decisions that will shape the Division of Science for years to come."