William Hennessy was born in 1839 and became an eminent painter of landscapes and figurative scenes.
He was born at Thomastown, Co. Kilkenny, in Ireland, but exhibited at the principal London galleries from 1871; chiefly at the Royal Academy and at the Royal Society of British Artists.
Hennessy worked for a time in America, but lived mainly in England and in France. Most of his painting work was completed either in Normandy or in Sussex.
William Hennessy died in 1920.