Pedro Gastão, whose name was after his father and grandfather, was born on 19 February 1913 in France in the Château d'Eu, at the homonymous town of Eu, Seine-Maritime, where the Brazilian Imperial Family was installed since 1905.

When Pedro Gastão was born, it had been five years since his father had signed the instrument of resignation, by which he theoretically would have renounced the rights of succession to the throne of Brazil for himself and his offspring.

[4] His position was supported by Francisco Morato, law professor at the University of São Paulo, who concluded the resignation of Pedro Gastão's father was not a valid legal or monarchical act.

[4] He represented a rival claim to that of his cousin's son, Luiz of Orléans-Braganza, to be the heir of the deposed Emperor Pedro II of Brazil, despite the renunciation signed by his father in 1908 when he married, without dynastic approval, a Bohemian noblewoman.

His dynastic claim to the head of the imperial house is currently assumed by his male grandson Pedro Tiago de Orléans e Bragança (born 12 January 1979).

Pedro Gastão died in the early hours of 27 December 2007, at the age of 94, and was buried the following day, in the chapel of Villamanrique de la Condesa.