Karen Donahue has been a Sister of Mercy for fifty-eight years. She has worked for peace and justice at the local, national and international levels serving in Sisters of Mercy community justice positions and at 8th Day Center for Justice in Chicago. She has traveled widely, visiting Latin America, Africa, the Middle East and Asia. She was part of two delegations to Honduras that were organized by the Sisters of Mercy Institute Justice Team. She has participated in three trips to Israel-Palestine with Meta (formerly Michigan) Peace Team and has taken part on civil disobedience actions at the Nevada Test Site, the School of the Americas, the Federal Courthouse in Detroit just before the start of the Iraq war in March 2003, and most recently at the Russell Senate Office Building in Washington, D.C. in support of DACA recipients in February 2018.

For the past eleven years, she has coordinated a weekly vigil in solidarity with immigrants at the Department of Homeland Security Office in downtown Detroit and twice a month visits immigrants detained at the Monroe County Jail in Monroe Michigan with Justice for Our Neighbors, the migrant ministry of the United Methodist Church. Currently she serves as a member of the Sisters of Mercy Justice Team. A native of the Chicago area, Karen has lived in downtown Detroit for seventeen years. She is an active member of St. Aloysius Parish in Detroit and received the 2013 Urban Parish Spirit Award.