He was educated in Roscrea and went on to study physiotherapy from which he became a phD graduate from University College Dublin.
With UCD, FitzGerald has won a Freshers All-Ireland in 2002 and a Walsh Cup medal in 2004.
He captained the Tipperary minor hurlers to munster final glory in 2001 against a highly fancied Cork side on a blistering hot day in Pairc Ui Chaoimh.
FitzGerald made his competitive debut at wing-back for Tipperary against Offaly in the 2004 National Hurling League.
Diarmaid won the RTE man of the match in Tipperary’s extra time replay victory over Limerick in May 2005.