[5] After three years of further studies in Rome, he was appointed in 1959–1967 as a faculty member and rector of the Seminary of Hoan Thiện, Huế.

Thuận, targeted for his faith as well as his family connections to Ngô Đình Diệm, was detained by the communist government of Vietnam in a re-education camp for 13 years, nine in solitary confinement.

Through a network of influential Overseas Vietnamese, including dignitaries, like his former classmate Monsignor Trần Văn Hoài, The Road of Hope was distributed worldwide.

On 24 November 1994, he was appointed President of the Pontifical Council for Justice and Peace, and at the same time resigned from his post of Coadjutor Archbishop of Sai Gon.

On 16 September 2007, the fifth anniversary of the cardinal's death, the Catholic Church began the beatification process for Thuận.

In the words of a catechist from the Archdiocese of Hồ Chí Minh City, "Nguyễn Văn Thuận is an example of holiness for Vietnamese Catholics and for the entire world.