The name Murphy originated from the Irish Gaelic Ó Murchadha or Ó Murchúda, which means "descendant of Murchadh" or "sea warrior". This Gaelic personal name Murchadh itself is derived from the Old Irish muir meaning "sea" and cath meaning "battle" or "warrior".

The name can be traced back to the early medieval period in Ireland, around the 9th or 10th century. It was initially given as a byname or nickname to those who had expertise in naval warfare or were known for their seafaring abilities.

One of the earliest recorded instances of the name Murphy is found in the Annals of Ulster, an ancient chronicle of medieval Irish history. It mentions a Murphy (Murchadh) who was the King of Leinster in the 10th century.

In the 12th century, during the Norman invasion of Ireland, the name Murphy gained prominence as many Irish families adopted hereditary surnames based on their ancestral first names. The Ó Murchadha clan was influential in counties such as Wexford, Kilkenny, and Tipperary.

Throughout Irish history, several notable figures bore the name Murphy, including Donal Óg Murchadha (c. 1530-1577), a Irish lord and military leader during the Desmond Rebellions against English rule, and Rory O'More (Ruairí Ó Mórdha, c. 1590-1655), a famous Irish outlaw and rebel who fought against English forces.

In the 17th century, the name Murphy also found its way to Scotland and England due to Irish migration and the Plantation of Ulster. One of the earliest recorded Murphys in England was Thomas Murphy (1585-1666), a judge and Member of Parliament during the English Civil War.

Other notable individuals with the name Murphy include Arthur Murphy (1727-1805), an Irish writer and playwright known for his plays "The Grecian Daughter" and "The Way to Keep Him", and John Murphy (1753-1798), an Irish Presbyterian minister and United Irishman who was executed for his role in the Irish Rebellion of 1798.