In 1820 the constitutional revolution triumphed in Portugal, and Feijó was sent as a representative from the province of São Paulo to the Portuguese assembly () in Lisbon, to which he was admitted 11 February 1822. On 25 April, he made an eloquent speech in defense of Brazilian rights, which were threatened by the Portuguese majority. The Brazilian deputies were unsuccessful, and Feijó, with five others, left Lisboa secretly for Falmouth, where, on 22 October 1822, they published a manifesto explaining their conduct. Feijó afterward returned to Brazil, and retired to Itu.