Isabel Luísa was the only child of Peter II of Portugal and his first wife, the French born Princess Marie Françoise of Savoy.

[4] In age five, Isabel Luísa was declared heir presumptive to the Portuguese throne during the 1674 Cortes.

The marriage was opposed by most of the Savoyard court as it meant that Victor Amadeus would live in Portugal and his mother would remain in power.

[9][8] Other proposed candidates included Gian Gastone de' Medici (future Grand Duke of Tuscany), le Grand Dauphin son of Louis XIV, Charles II of Spain,[4] the Duke of Parma as well as a Count Palatine of Neuburg.

Isabel Luísa is buried at the Monastery of São Vicente de Fora in Lisbon after being moved from the Convent of the Francesinhas.