In the 1940s, Henrique Galvão, Angolan deputy to the Portuguese National Assembly, read his "Report on Native Problems in the Portuguese Colonies". Galvão condemned the "shameful outrages" he had uncovered, forced labour of "women, of children, of the sick, [and] of decrepit old men." He concluded that in Angola, "only the dead are really exempt from forced labor" and claimed that as much as 30% of all Angolan forced labourers died. He accused the government's control over the natives of eliminating the worker-employer's incentive to keep his worker in good shape because, unlike in other colonial societies, the state replaced deceased native workers without directly charging the employer. The Portuguese government refuted the accusations and ignored Galvão's report. He would be arrested in 1952. He was compulsorily retired from the military career and was awarded a state pension. In 1959, an anti-regime activist, he escaped from Portugal to Venezuela.

In the 1960s, shortly before the events that would led to the Portuguese Colonial War against several African independence guerrillas, Galvão led the Santa Maria hijacking, also known as Operation Dulcinea, on January 22, 1961. The terrorists, led by Henrique Galvão, seized the ship, ceased all communication, killed one officer and wounded several others in the procesc of taking complete command over the ship. The rebels forced crew members, along with the captain of the ship, Mario Simões Maia, to take the ship on a different course. Galvão used the hijacking and radio broadcasts from the ship to call attention to Portuguese fascism. The event received wide international press coverage. The liner evaded both the U.S. and British navies for eleven days before docking safely at Recife, Brazil. On February 2, 1961 the hijackers were met by Brazilian officials off the coast of Recife. Galvão released the passengers in negotiation with Brazilian officials in exchange for political asylum. Galvão later announced that his intentions were to sail to the Portuguese overseas province of Angola, to set up a renegade Portuguese government in opposition to António de Oliveira Salazar's regime. Galvão remained exiled in Belo Horizonte, Brazil where he died.

His published works include "Da vida e da morte dos bichos" (life and death of wild african animals, as elephants, rihnos, lions, cheetas, bufalos,etc) published in five books and "Outras Terras, outras Gentes".