Born in Seattle, Washington, in 1953. Zappone was educated at Boston College (PhD), The Catholic University of America (MA) and University College Dublin (MBA). She became an Irish citizen in 1995. She and her wife, Ann Louise Gilligan, founded An Cosán which supports individuals and communities to actively engage in the process of social change through transformative education. In "Zappone and Gilligan v. Revenue Commissioners" (2006), they unsuccessfully sought recognition in the High Court, for their Canadian marriage in Ireland. Zappone was a member of the Irish Human Rights Commission, chief executive of the National Women's Council of Ireland, and a lecturer in the fields of ethics, theology, and education at Trinity College, Dublin. Though they were already married in Canada, Zappone proposed to Ann Louise Gilligan on air as the positive result in the same-sex marriage referendum became known. Gilligan died in June 2017.