Her maternal grandparents were Philip II of Spain and Elisabeth of Valois, her paternal grandparents were Emmanuel Philibert, Duke of Savoy and Margaret of France, Duchess of Berry.

Isabella was born in Turin to Charles Emmanuel I, Duke of Savoy[1] and his wife Infanta Catherine Michelle of Spain, a daughter of Philip II of Spain and Elisabeth of France.

On 22 February 1608, she married Alfonso, Hereditary Prince of Modena (son of Cesare d'Este and Virginia de' Medici) in Turin.

[2] This was a happy marriage; Alfonso was loving and loyal towards his wife.

Within two years, Isabella bore Alfonso a son, Francesco who would one day succeed his father as Duke of Modena and Reggio.