Joanna was born in 1573 to John of Austria, victorious admiral of the Battle of Lepanto of 1571, and the Sorrentine lady Diana Falangola.

[1] She was named after her aunt Joanna of Austria, a widowed princess of Portugal, who died a few days before her birth.

[2][3] After the death of Philip II in 1598, her luck did not change and the Duke of Lerma ordered the viceroy of Naples, Fernando Ruiz de Castro Andrade and Portugal to continue the regime established until then.

Finally in 1602 Joanna wrote a letter to Philip III in which she begged him for economic independence that would allow her to not depend on the viceroy of Naples.

[6] She founded the Church of Santa Maria della Vittoria in Naples [it] and donated it, together with its convent, to the Theatine Fathers.