[4][5] Her mother, Teodora de Viana Martins Caeiro, was from Galicia, northern Spain, and went to live first in Amareleja and then in Lisbon, while Celeste's father left the family when she was a child.
At the age of 20, she started her pre-nursing studies at the Santa Clara de la Casa Pia College, but due to lung problems, she never practiced this profession.
[4] In 1974 Caeiro was working in a self-service restaurant in Lisbon called "Sir" located at Franjinhas Building on Rua Braamcamp as a cleaner.
[5] She approached two soldiers mounted on a Bravia Chaimite truck to ask what was going on, to which one replied that they were heading to Quartel do Carmo to arrest Prime Minister Marcelo Caetano and that a revolution had broken out.
[10][5][6] The same man asked her for a cigarette, but as Caeiro did not smoke and in compensation for the "good news" he had given her, as she said shortly afterwards, she gave him a carnation from the bouquet she was carrying and he put it in the barrel of his gun.
[10][6] From then on, from Chiado to the Basilica of Our Lady of the Martyrs she gave the rest of the carnations to the soldiers involved, and they placed the flowers in the muzzle of their guns.
[4] On 7 May 1974, journalist António José Saraiva [pt] wrote in the newspaper República that "the red carnation of Freedom has no known author, it was not proposed or programmed by any organisation.
[7] In 2024, she took part in the parade commemorating the 50th anniversary of the Carnation Revolution on Avenida da Liberdade in Lisbon alongside her daughter and granddaughter.
[10][15][3] Her death was mourned by Prime Minister Luís Montenegro who stated that "in this hour of mourning, I leave a word of recognition for Celeste Caeiro", and the President Marcelo Rebelo de Sousa expressed his sadness and announced that she would be decorated posthumously, while the Armed Forces published a message saying that "Celeste Caeiro, with an apparently simple gesture, became the symbol of a movement that changed Portugal forever" and "her legacy will remain alive in history and in the memory of all of us".