Muldoon as a name is an anglicised form of the Gaelic Ó Maoldúin (meaning descendant of Maoldúin), a personal name composed of the elements maol (chieftain) and dún (fortress).

The Muldoon surname is said to have been first found in County Sligo, Ireland, where they had been anciently seated at Enniscrone and said to be directly descended from King Niall of the Nine Hostages, Ireland’s General Commander/King who died in the fourth century.

Septs (clans) with this name were located in Counties Fermanagh, Clare and Galway and it is in these Counties that the majority of descendants can be found.

The family motto “Pro fide et patria” translates as “For faith and my country”.