Saint François Jaccard (Vietnamese name: Phan) was born on September 6, 1799, in the village of Onion, Savoie, France, into a devoutly religious family. Despite facing many difficulties in his studies, he was ultimately ordained a priest of the Paris Foreign Missions Society and set out on his missionary journey.

On July 10, 1823, he departed for the Far East, passing through India, Macau, and finally arriving at the Đàng Trong Diocese (Vietnam) on January 5, 1826. Here, he learned Vietnamese, took the name Jaccard - Phan, and was appointed to pastoral ministry at the parishes of Nhu Lý and Phủ Cam, while also serving as the director of the An Ninh Seminary.

During the time when King Minh Mạng banned the faith, Father Phan was arrested for the crime of preaching. The initial death sentence was changed by the king to "imprisonment pending later execution." In reality, he was taken to the capital city of Huế to work as a translator. Later, following the queen mother's wish, the king changed his sentence to life exile at the Lao Bảo Pass. In 1835, he was recalled to Cam Lộ to continue translation work and teaching French.

In a letter to his mother, Father Phan expressed: "In a short time, I will not have to suffer anymore; I wish to die for the holy faith in this country."

In the Spring of 1838, when the seminaries at Di Loan and An Ninh were discovered and destroyed, the king suspected Father Phan of collusion. On March 17, 1838, he was taken to Quảng Trị, where he endured caning, exposure to the sun, and many other tortures for resolutely refusing to renounce his priestly vocation.

Finally, the death sentence was carried out. On the way to the execution ground, Father Phan and seminarian Trần Văn Thiện were given absolution from a distance by the elderly priest An, according to a pre-arranged signal. On the morning of September 21, 1838, both were executed by strangulation at the Nhan Biều execution ground, Quảng Trị. Their bodies were buried by the riverbank. In 1847, their remains were exhumed and brought to the Chapel of the Paris Foreign Missions Society for veneration.

Upon hearing the news of her son's martyrdom, Father Phan's mother said: "This is truly joyful news; our family has a martyr. Praise be to God."

Priest François Jaccard - Phan was beatified on May 27, 1900, and canonized on June 19, 1988.