A Catholic priest and essayist, Ly has spent over 15 years in prison for the causes of human rights and religious freedom. Most recently, he was released in 2016, ahead of a visit by U.S. President Barack Obama, after serving an eight-year sentence for his role in the Bloc 8406 Manifesto on Freedom and Democracy for Vietnam. Ly is also a co-editor of the underground online magazine Tu Do Ngon Iuan (Free Speech).