Professor Miller's research lies at the intersection of Chinese religions, ecology and, more recently, astrobiology. He is the editor-in-chief of the journal Worldviews: Global Religions, Culture and Ecology, and of the forthcoming Oxford Handbook of Daoism. He has published three monographs, two edited volumes, two co-edited volumes, and fifty articles or book chapters on Chinese religions, and his work has been translated into Farsi, Korean, Chinese and Italian. In 2023 he held a senior distinguished visiting fellowship at the Library of Congress, Washington, DC. He is also the recipient of an Apereo Atlas Teaching Award for his work on the DKU core course China in the World.

Miller holds a BA in East Asian Studies from Durham University; an MA in Theological and Religious Studies from Cambridge University; and a PhD in Religious and Theological Studies from Boston University. Prior to joining DKU he served as director of the graduate program in Cultural Studies and director of the School of Religion at Queen's University, Canada.