He is a past Convener of the Black Catholic Theological Symposium and a former president of the Catholic Theological Society of America. Massingale strives to be a scholar-activist through serving faith-based groups advancing justice in society. He has served as a consultant to the United States Catholic Conference of Bishops, providing theological assistance on issues such as criminal justice, capital punishment, environmental justice, and affirmative action. He has also been a consultant to the National Black Catholic Congress, Catholic Charities USA, the Catholic Health Association, Catholic Relief Services, the Leadership Conference of Religious Women, the Conference of Major Superiors of Men, the National Catholic AIDS Network, and the antiracism teams of Call to Action and Pax Christi USA. He is an active participant in a network of Catholic thought leaders striving for fuller inclusion of LGBT persons in society and the faith community. He is the author of Racial Justice and the Catholic Church.