From a Norman French name, Raulf, a contracted form of the Germanic personal name Radulf, derived from rād ‘counsel’ + wulf ‘wolf’. The spelling with -ph is due to classical influence in the 18th century.
Irish (Kerry): shortened Anglicized form of Gaelic Ó Muircheartaigh ‘descendant of Muircheartach’, a personal name composed of the elements muir ‘sea’ + ceardach ‘skilled’, i.e. ‘skilled navigator’. A Meath and Monaghan name of the same form is Anglicized as Murtagh.