He is the peacebuilding coordinator for the Mennonite Central Committee (MCC) Kenya. He joined MCC in June 2014 after several years of work in peacebuilding and conflict resolution. His work has focused on faith-based peacebuilding interventions, grassroots civil society development, and fostering democratic political culture in transitional societies. William has trained peace workers in the Philippines, worked with political parties, assisted the peace process in Kenya, and has been involved in peacebuilding interventions in Uganda and Tanzania. He served as the peacebuilding and research adviser for the Catholic Relief Services (CRS) in the Philippines and Kenya, as well as for the National Council of Churches of Kenya. He holds a Master’s Degree in International Peace Studies from University of Notre Dame, a Bachelor's Degree in Counseling from Kenya Methodist University, and a Diploma in Peacebuilding and Conflict Transformation from Mindolo Ecumenical Foundation, Kitwe, Zambia.