Saint Joseph Marchand was born on August 17, 1803 in a poor family in the Diocese of Besançon, France.
In 1826, Marchand entered the Besançon Seminary. Two years later, Father Marchand asked to join the Paris Foreign Missions Society and was ordained a priest on April 4, 1829. On the day of his ordination, the newly ordained priest Joseph Marchand wrote to his family: "Dear parents, I no longer hope to see my family on earth, for I have set foot on the path of evangelization. May the Lord grant me the grace to never look back."
Arriving in Nam Ky (southern Vietnam) in 1830, Father Marchand learned Vietnamese, taking the Vietnamese name Du, and ministered to Vietnamese Catholics in Phnom Penh. After some time, Father Marchand-Du was put in charge of a group of seminarians at Lai Thieu and 25 parishes, with around 7,000 faithful.
After King Minh Mang's decree banning Catholicism on January 6, 1833, Bishop Tabert-Tu, Father Cuenot-The and the missionaries fled with the seminarians to Thailand. Only Father Du resolutely remained, hiding in the Six Provinces region, assisting the parishes of Cai Nhum, Cai Mon, Bai Xan, Giong Rum and residing in Mac Bac, Vinh Long.
On July 6, 1833, angered by King Minh Mang's order to whip 100 times the tomb of General Le Van Duyet, Le Van Khoi, the adopted son of General Le Van Duyet, took the pretext of supporting the grandson of King Gia Long, Prince Canh's son, to rebel against the royal court. The affair was exposed, Khoi was arrested but escaped, then gathered troops to seize Gia Dinh citadel and the Six Provinces region in July 1833.
Through clever promises to lift the court's ban on Catholicism, Khoi gained some Catholic followers. To be able to rally more Catholics, Khoi invited Father Du to the citadel but the Father resolutely refused. Later, fearing that if he did not come, Le Van Khoi would harm the faithful, the priest reluctantly went to the parish of Cho Quan, in the outskirts of Gia Dinh citadel.
When the royal troops besieged Gia Dinh citadel, Le Van Khoi had his soldiers force Father Marchand-Du into the citadel. However, the Father always said: "I only know religious matters, not the profession of battle." Khoi forced the priest to sign a letter calling on the people and the faithful to rise up against the king, but the Father threw it all into the fire. After two years, Gia Dinh citadel fell, Father Marchand-Du was arrested, beaten, and locked in a small cage forcing him to sit hunched over day and night.
On October 15, 1835, along with four prisoners, Father Marchand-Du was escorted to the capital Hue. Despite being tortured many times with red-hot iron tongs, Father Du adamantly denied assisting Le Van Khoi's rebellion, affirming: "I only preached the Gospel, prayed to the Lord and celebrated Mass."
King Minh Mang sentenced the priest on two charges: being the leader of the Western religion and supporting Le Van Khoi's rebellion. The death sentence by beheading was carried out on November 30, 1835. Afterwards, the priest's body was thrown into the sea, with no one able to keep any relic of this saint.
Priest Joseph Marchand-Du was beatified on May 27, 1900 and canonized a saint on June 19, 1988.