Saint Joseph Nguyễn Duy Khang was born in 1832 in Cao Mại village, Trà Vi commune, Vũ Tiên district, Thái Bình province. His father passed away early, and he was raised by his mother to become a calm, courageous, and pious person.

In 1845, the young Khang entered the household of God and was cared for and taught for nearly ten years by Father Matthêu Năng, of the Dominican Order. Afterwards, he received the Dominican habit and was sent to the Kẻ Mốt Seminary to prepare for ordination to the priesthood.

On August 5, 1861, King Tự Đức issued an edict dispersing the faithful, intensifying the persecution of the Catholic faith. The Kẻ Mốt Seminary was closed and later destroyed. Bishop Hermosilla (Liêm) was forced to flee from Kẻ Mốt village and took refuge in a cave in Thọ Ninh. It was God's will that the catechist Khang follow and assist the Bishop. Though just 29 years old, he arranged everything and dedicated himself to protecting the religious leader.

Both were captured and taken to the district mandarin's office (công đường) in Hải Dương. On January 1, 1862 (Note: The original text states 1851, but based on the historical timeline, this appears to be a typo and should be 1862, consistent with the narrative), Bishop Hermosilla was beheaded. Catechist Khang was imprisoned for over a month and suffered two horrific torture sessions. The first time, he was brutally beaten for refusing to reveal the hiding places of the religious leaders. The second time, he was struck with 120 lashes. While in prison, living among fellow Catholics, he still organized communal prayer and performed acts of penance and reparation to prepare to receive the grace of martyrdom.

Previously, he had said: "If the mandarins arrest Bishop Hermosilla (Liêm), they will certainly not spare me. If the Bishop is granted the grace to die for the Faith, then I too would receive that grace."

On December 6, 1861, Catechist Joseph Nguyễn Duy Khang suffered beheading at the Năm Mẫu execution grounds (Hải Dương) and was buried at the very site of his execution. In 1867, his remains were exhumed and reinterred in the chapel of the Kẻ Mốt congregation.

Catechist Joseph Nguyễn Duy Khang was beatified on May 20, 1906, and was canonized on June 19, 1988.