O'Malley comes from a political family. Her father, Desmond O'Malley, was a former Fianna Fáil cabinet minister and founder of the Progressive Democrats. Her granduncle, Donogh O'Malley, was a Fianna Fáil minister in the 1960s. She is also a cousin of another former Progressive Democrats TD, Tim O'Malley.
She was a member of the Oireachtas Committee on Arts, Sports and Tourism and the Oireachtas Committee on Health and Children. She was also a member of the Dáil All-Party group concerned with matters of sexual and reproductive health. She has travelled to South America and South Africa with the United Nations Population Fund and has spoken extensively of the need for a clear safe sex message both in Ireland and in the developing world.