Leighton holds an M.A. from the California Institute of Integral Studies and a Ph.D. from the Graduate Theological Union in Berkeley, where he has taught since 1994, alongside teaching appointments at Loyola University Chicago and other institutions. In 2007 he relocated to Chicago to become founding Guiding Dharma Teacher of Ancient Dragon Zen Gate, a role he held through mid-2024. He is an authorized teacher (kyōshi) in the Japanese Sōtō school and has long been active in peace and environmental activism.
Leighton has authored roughly ten books of commentary and translation on Zen texts, including Faces of Compassion: Classic Bodhisattva Archetypes and Their Modern Expression, Visions of Awakening Space and Time: Dōgen and the Lotus Sutra, Zen Questions: Zazen, Dōgen, and the Spirit of Creative Inquiry, and Realizing Genjōkōan: The Key to Dōgen's Shōbōgenzō, as well as co-translations of major Dōgen works such as Dōgen's Extensive Record: A Translation of the Eihei Kōroku and Cultivating the Empty Field: The Silent Illumination of Zen Master Hongzhi.