At the age of 36, Tuấn was arrested and taken to Xuân Trường district, then later reassigned to the village of An Bái in Thụy Anh district. In August 1861, carrying out the royal edict banning Christianity, soldiers used knives to carve two characters, "tả đạo" (false religion), onto his left cheek and the name of his village onto his right cheek. The harsh months in prison, lacking even food and water, caused his health to deteriorate severely.

Thinking that a person in such dire straits would easily waver in their resolve, the provincial chief believed this was an opportune moment to force him to renounce his faith, so that he might return and be reunited with his family. But that official was mistaken. That simple, honest farmer remained utterly faithful and steadfast, showing no fear in the face of the death sentence. Supported by extraordinary grace, he courageously professed his unshakeable faith in Christ. Before the mandarins and soldiers, not only did he refuse to step over a holy image, but he knelt down and reverently kissed an image of Christ the Redeemer.

On June 7, 1862, on the way to the execution grounds in Nam Định, that gentle farmer quietly knelt down on a small flowered mat, whispering the most holy name of Jesus before the executioner carried out the beheading. Two years later, his remains were solemnly brought back by the faithful and interred within the grounds of Nam Điền church.

The heroic example of this witness to the faith, Joseph Trần Văn Tuấn, was honored by the Church. On April 29, 1951, he was raised to the rank of Blessed, and on June 19, 1988, he was canonized as a Saint.