The Castle is set on the hilltop in a strategic position over the valley of the River Fredane.
It was built by the Lombards and soon became one of the most important Fortresses in Irpinia. The original hamlet was centred around the Castle. The first mention of Gesualdo dates back to 1078, its lord was a certain Guglielmo of Gesualdo. Over the years, many aristocratic families held the fief until it passed to Carlo Gesualdo, Prince of Venosa. He is famous for his intensely expressive madrigals, and also for committing what are amongst the most notorious murders in musical history. In 1590, upon surprising his beautiful wife Maria d'Avalos with her lover Fabrizio Carafa, he killed them both. Being a nobleman he was immune to prosecution, but not to revenge, so he fled to his Castle in Gesualdo where he would be safe from any of the relatives of either his wife or her lover. In his Castle he dedicated the last years of his life to sacred music. Carlo Gesualdo transformed his Castle into a magnificent residence when he got married the second time with Eleonora D'Este.
Today the Castle has a rectangular layout with round Towers, some balconies and windows dating back to the 19th century.