Green's work is focused on the ethics of space exploration and use, as well as the ethics of technological manipulation of humans, and various aspects of the impact of technology and engineering on human life and society, including the relationship between technology and religion (particularly the Catholic Church).

Green received his doctoral and master's degrees in ethics and social theory from the Graduate Theological Union in Berkeley. His earned his undergraduate degree in genetics from the University of California, Davis. Between college and graduate school, he served for two years in the Jesuit Volunteers International teaching high school in the Marshall Islands.

He is co-author of the Ethics in Technology Practice corporate technology ethics resources. Green is also co-chair of the Responsible Use of Technology group at the World Economic Forum and is a member of the Safety-Critical AI expert group at the Partnership on Artificial Intelligence to Benefit People and Society. He also helps to convene several academic discussion groups on AI and human nature involving the Vatican’s Pontifical Council for Culture.