Born in Dingle Co. Kerry, Ian grew up in Limerick. He went to school in Ardscoil Ris and went onto complete an Honours Degree in Sport Science at the University of Limerick.
A former centre and out-half, Costello has been working with the Munster Rugby squad since 2010. He has held roles at Munster U20, A and Academy level. A former Director of Rugby at UL Bohemians RFC, the Limerick based coach assisted Anthony Foley with the Munster U20s and Munster A's before assuming the role of Munster A Head Coach in 2011 and leading the side to a British and Irish Cup title. He has been credited for aiding the skill development of Munster's current rising stars.
Costello takes on the role of Assistant Coach with responsibility for Defence and Kicking from July 2014.