The seating in the stalls, consisting of mahogany chairs, was removable and the floor could be raised to the level of the stage, thus creating a ballroom.

[1] At the Trindade, Francisco Palha introduced what he called "burlesque opera", with Delphina and Amélia Barros being among the leading performers.

In 1901, management was taken over by Afonso Taveira, who was responsible for guiding the Trindade through the period of instability that included the regicide, the First Portuguese Republic and the beginning of World War I, until his death in 1916.

Theatrical groups to play there included the Amélia Rey Colaço-Robles Monteiro company, the Portuguese Opera Company (CPO), the Comedians of Lisbon (Os Comediantes de Lisboa) run by Francisco Carlos Lopes Ribeiro and his brother António and the Teatro Nacional Popular.

[1][2] In 1962 FNAT, the National Foundation for Happiness at Work (Fundação Nacional para Alegria no Trabalho), an organization promoted by Portugal’s authoritarian Estado Novo government, acquired the Teatro da Trindade.

In 1967, remodelling work was carried out, under the direction of Maria José Salavisa, who chose the blue and gold interior decoration that remains today.

The theatre continues to be owned and operated by the successor organization to FNAT, known as the National Institute for the Use of Workers' Free Time (Instituto Nacional para o Aproveitamento dos Tempos Livres), or INATEL.