Marie Jeanne Baptiste was born in Paris, on 11 April 1644, the daughter of Charles Amadeus of Savoy, 6th Duke of Nemours (1624–1652) and Elisabeth de Vendôme, herself a granddaughter of Henry IV, King of France via her father César de Bourbon, duc de Vendôme.
In 1662 Marie Jeanne Baptiste was engaged to Charles V, Duke of Lorraine, but on 10 May, 1665 she married Charles Emmanuel II, Duke of Savoy (1634-1675). They had one son, Victor Amadeus, future Duke of Savoy and King of Sicily and Sardinia.
After the early death of her husband, Marie Jeanne Baptiste became Regent of Savoy in the name of her underage son. An energetic and ambitious woman, she called herself Madama Reale in honor of her respected mother-in-law Christine de France, (also half sister of César) who had also reigned as a regent of Savoy.
She tried to gain the throne of Portugal for her son by engaging him to his cousin Isabel Luísa, Princess of Beira, only child and presumptive heiress of her father, Peter II of Portugal. This would have left Marie Jeanne Baptiste permanently in full control of the Duchy of Savoy as Regent because her son would have had to live in Portugal with his new wife.
Retired from politics, she still had a great influence over her granddaughter Princess Marie-Adélaïde of Savoy, who married Louis, Duc de Bourgogne in 1697 and who became Dauphine in 1711. She instructed the young girl in the ways of the French court of Louis XIV by means of a continuing correspondence.