Her parents" marriage was unhappy and they lived separated from each other. They only produced two children: Maria Beatrice, born on 7 April 1750 and Rinaldo Francesco, born on 4 January 1753. The death of Rinaldo aged four months old (5 May 1753) led to Maria being acknowledged as an heiress.
Her paternal ancestors included Louis XIII of France and Philippe d"Orléans, Regent of France for Louis XV. As heiress to four states (Modena, Reggio, Massa and Carrara), she was a very attractive wedding partner.
Empress Maria Theresa sought to arrange a marriage between Maria Beatrice and the Archduke Leopold (future Holy Roman Emperor) but this never materialised. The couple was engaged from 1754.
As the children were so young, the marriage was not celebrated till 1771 when a ceremony in Milan on 15 October officially united them. Festivities arranged for this occasion included the operas Ascanio in Alba by Mozart and Il Ruggiero by Johann Adolph Hasse.
The couple moved between Modena and Milan, where they lived in the Royal palace.
When her mother died in 1790, however, she succeeded her as Duchess of Massa and Carrara. After the French conquest of Northern Italy, she spent her life mostly in Austria and left the rule to administrators. After Maria Beatrice d"Este"s death at Vienna in 1829, Massa and Carrara were added to the Duchy of Modena.
Her maternal ancestors were members of the House of Cybo-Malaspina, members of the Italian nobility.