He is the co-founder, with Judy Carman, of the Circle of Compassion and the Worldwide Prayer Circle For Animals. He has lectured through Unity Church and other New Thought and progressive centers throughout North America since 1990, and was the first guest of Animal Rights Zone in 2010. He made an international debut in August 1995 at the 8th International Vegan Festival in San Diego, where he performed inspirational classical music and spoke about inner and outer peace and harmony in the context of a vegan diet. Tuttle is a former Zen monk who studied in Korea. He obtained his master's degree in humanities from San Francisco State University and his PhD from the University of California, Berkeley, specializing in the philosophy of education. He is a frequent speaker at vegetarian, spiritual, and animal rights conferences and at local vegetarian societies. He and Steve Prussack organized the Veganpalooza online audio conference (11–15 June 2012) and has organized other online events and conference calls on the theme of veganism and world peace. Tuttle has been a vegan since 1980.