Mai was the inaugural director of Eleos Justice (October 2020-July 2024), before she was appointed as the Special Rapporteur on the situation of human rights in the Islamic Republic of Iran. From February 2025, she will be Professor and Director of the Institute for Crime and Justice Policy Research, in the Faculty of Humanities and Social Sciences at Birkbeck, University of London.

Mai is a social scientist by training and has led and worked on projects on the death penalty in Japan, Malaysia, the Philippines, India, Kenya, and Zimbabwe. Her monograph The Death Penalty in Japan: Will the Public Tolerate Abolition? (Springer, 2014), and her documentary film which captured a social experiment exploring what the death penalty meant to ordinary Japanese citizens, influenced the decision by the Japan Federation of Bar Associations to become an abolitionist organisation in 2016.