She is venerated in the Catholic Church with the title 'Blessed', is commemorated by a feast on May 12, and is commonly known in Portugal as Holy Princess Joan (Portuguese: Santa Joana Princesa).

Joanna was the second child of Afonso, but after the early death of her older brother John in 1451, she was recognized as heir presumptive and given the title of Princess of Portugal.

Upon the birth of her younger brother, the future John II of Portugal in 1455, she ceased to be heir presumptive, but among the people she continued to be known as Princess Joanna.

After vehemently refusing several proposals of marriage,[1] Joanna joined the Dominican Convent of Jesus in Aveiro in 1475.

[2] Her brother had by then fathered an heir, so the family line was no longer in danger of extinction, and thus she entered the convent that same year her nephew Afonso was born in 1475.

This was to be part of a double marital alliance, with his niece Elizabeth of York marrying her cousin, the future Manuel I.