Valladares was a Cuban Postal Bank employee. He was arrested when he refused to display a sign on his desk that promoted communism. Valladares was jailed in 1960, at age 23, when the new government arrested him on charges of being a counter-revolutionary. Valladares spent 22 years in prison. He was adopted by Amnesty International as a prisoner of conscience, and an international campaign for his release was led by his wife Marta. Many artists joined it, for example Jacek Kaczmarski. The campaign culminated in French President François Mitterrand making a personal appeal to Fidel Castro. Valladares was freed after spending 22 years in prison. He then moved to the United States.

Amnesty International's Secretary General in Norway described Valladares as the "embodiment" of a "prisoner of conscience" and referred to him as "arrested and sentenced for thirty years in prison not for something he did but for something he refused to do and that was to become part of Fidel Castro's propaganda machine." [1]

Valladares's memoir, Against All Hope - which details his incarceration in Cuban prisons - became an international best-seller. On the advice of his daughter Maureen, President Ronald Reagan appointed Valladares to serve as the U.S. Ambassador to the United Nations Human Rights Commission. As Head of the U.S. Delegation, he successfully brought Cuba before the Commission for its human rights violations. President Reagan would later confer on him the nation’s second-highest civil honor, the Presidential Citizens Medal. The Cuban workers' newspaper, Trabajadores described the appointment as "a disgrace".

Valladares has addressed the United Nations General Assembly and legislative groups in Europe and the Americas. He is currently the President of the Valladares Project, an international non-profit organization which advocates children’s rights.

Valladares is the former Chairman of the International Council of the New York-based Human Rights Foundation. He resigned July 7, 2009, in support of Honduras's democratic institutions, publishing a public resignation letter with title "I am in total disagreement with what you published regarding Honduras". In it he pointed out the background to the 2009 Honduran constitutional crisis, calling Zelaya's plans illegal. In November 2009 he was decorated with the "José Cecilio del Valle" medal by Honduras's interim president Roberto Micheletti, together with Alejandro Peña Esclusa and Juan Dabdoub Giacoman, who had also been outspoken defenders of the country during the crisis.

Valladares was one of the closest friends of Pedro Luis Boitel.

He signed his name to a full-page ad in the Dec. 5, 2008 New York Times that objected to violence and intimidation against religious institutions and believers in the wake of the passage of Proposition 8. The ad stated that "violence and intimidation are always wrong, whether the victims are believers, gay people, or anyone else." A dozen other religious and human rights activists from several different faiths also signed the ad, noting that they "differ on important moral and legal questions," including Proposition 8..

Since his release, the Cuban regime has described Valladares as a terrorist and a fraud. Cuban officials allege that Valladares was a former member of the secret police of Cuban dictator Fulgencio Batista, who was toppled by the 1959 Cuban revolution.

In 2004, Felipe Pérez Roque, Minister of Foreign Affairs of the Republic of Cuba, said: "That is Armando Valladares, a cop from Batista’s dictatorship, detained — that is the press of the time — for placing in public places bombs packed in cigarette boxes; a member of a terrorist cell in which Carlos Alberto Montaner also participated. They were convicted and for that reason Armando Valladares went to prison in Cuba" .

During his captivity, Valladares claimed to be partially paralyzed (and in need of a wheelchair) as a result of mistreatment in prison. Fidel Castro has claimed in an interview that Valladares agreed to stop pretending to be paralyzed as a condition of his release.