On July 4, 2008, Power married law professor Cass Sunstein, whom she met while working on the Obama campaign. They were married in the Church of Mary Immaculate, Lohar, Waterville, County Kerry, in Ireland. On April 24, 2009, she gave birth to their first child, Declan Power Sunstein. On June 1, 2012, she gave birth to their second child, a daughter, Rían Power Sunstein.