Education
University College Dublin.
Member of the European Parliament politician
University College Dublin.
A native of County Louth she has a Bachelor of Arts and a H.Dip. in Education from University College Dublin. She was elected in 2004 and re-elected in June 2009. She was elected Lord Mayor of Dublin by a unanimous vote of the city council at its annual meeting on 15 June 2009.
Costello has observed international elections in Cambodia, South Africa and Bosnia.
Her sister is Senator Mary Moran. Costello replaced Proinsias De Rossa in the European Parliament when he resigned as Member of the European Parliament in February 2012.
She lost her seat at the 2014 European Parliament election.
She was a South&Doctorate Member of the European Parliament (Member of the European Parliament) for Dublin from February 2012 to May 2014. She was a member of Dublin City Council from 2003 to 2012, and was Lord Mayor of Dublin from 2009 to 2010.