Justin Huntly McCarthy was an Irish writer, historian, and nationalist politician. He was a Member of Parliament (MP) from 1884 to 1892, taking his seat in the House of Commons of the United Kingdom.

The Vagabond King is a 1925 operetta by Rudolf Friml in four acts, with a book and lyrics by Brian Hooker and William H. Post, based upon Justin Huntly McCarthy's 1901 romantic novel and play If I Were King. The story is a fictionalized episode in the life of the 15th-century poet and thief François Villon, centering on his wooing of Katherine De Vaucelles, and relating how he becomes “king for a day” and defends France against the invading forces of the Duke of Burgundy.