Philip Murphy was born on 19 December 1869 in Island, with his birth officially registered in the district of Virginia within the Union of Oldcastle, County Cavan. His father, Bernard Murphy, recorded his occupation as a farmer.

He was baptised on 17 December 1869 in the local parish. His baptismal sponsors were Bernard Murphy and Mary Reilly.

A minor discrepancy appears in Philip’s official records, with his civil birth registered on 19 December 1869, while his church baptism was recorded just prior on 17 December 1869. In nineteenth-century Irish genealogical research, when a baptism and civil birth date appear to conflict by a day or two, church baptismal records—which were written down contemporaneously by the clergy at the ceremony—are generally considered very reliable indicators of the actual timeframe of birth, while civil records capture the official administrative registration.