Sinead graduated from National University of Ireland, UCD with a BCL in 1988 and, having graduated from The Honorable Society of Kings Inns with a Degree of Barrister at Law, was called to the Irish Bar in 1990. On foot of an award of a scholarship by the Department of Education Sinead completed a bilingual postgraduate course in EC law at the College of Europe in Bruges, following which she did a stage at DG IV of the European Commission in Brussels.
Sinead then spent a total of eight years working as a legal adviser to major Irish financial institutions. During that time she graduated with an LL.M. (with special mention) in Commercial Law from UCD. Before taking up the position of Teaching Assistant at University of Limerick, Sinead spent two years at O Donnell Sweeney, Solicitors in Dublin.