Born to Jack Dempsey (originally from Laois) and Annie Spain (originally from County Offaly), Dempsey is one of seven children: the others are Martin, P. J., Seán, Betty (Moore), Margaret (Farrelly) and Anne Dempsey all of whom have links with the St Joseph's club.
[1] Dempsey captained his club St Joseph's to the Laois Senior Football Championship title in 1983.
With the Carlow club O'Hanrahans coach, Dempsey led the Blues to three championships and a Leinster title (2000) in his four-year tenure.
He also managed the Muckalee and St Martins clubs in Kilkenny before joining manager Brian Cody as part of the leadership team for the Kilkenny senior hurlers in 2003.
[2] Dempsey stepped down as part of the Kilkenny hurling backroom team in October 2019.