He was part of Derry's 1993 All-Ireland Senior Football Championship winning side, also winning two Ulster Championships and four National League titles with the county.
While young, Cassidy's childhood football heroes were Derry's Anthony Tohill, Seán Óg de Paor of Galway and Donegal's Anthony Molloy.
Anthony Hopkins | Anthony van Dyck | Marc Anthony | Anthony Eden | Anthony Quinn | Anthony Braxton | Susan B. Anthony | Anthony Burgess | Anthony Trollope | Anthony | Anthony Kennedy | Anthony of Padua | Anthony Wayne | Anthony Bourdain: No Reservations | Anthony Powell | Anthony Caro | Anthony Bourdain | Anthony Blunt | Anthony Newley | Anthony Head | St. Anthony | Carmelo Anthony | Anthony LaPaglia | Anthony Kenny | Piers Anthony | Mark Anthony | Anthony Minghella | Anthony the Great | Anthony Michael Hall | Anthony Kiedis |