[1][2][3][4] MacCarthy was born into an Irish shipping and coal merchant family of Wellclose Square, East London.

[1] After receiving his education at the Roman Catholic school, St. Edmund's College, MacCarthy resided a number of years on the continent.

Being of independent means, MacCarthy initially focused on producing historic novels, including: The Siege of Florence, Massaniello and The Free Lance.

His scheme to buy out his ancestral property in the neighbourhood of Dunmanway, including the castle at Togher, was never fulfilled.

[1][3] Daniel's paternal grand-uncle Denis emigrated from Dunmanway in the mid-1700s, and became a prosperous shipowner and coal merchant in London.