Born in 1813 in the Tắt parish, Long Đại village, Gò Công region (now part of Biên Hòa), Mr. Matthew Lê Văn Gẫm was the eldest son in a family of six children. At age fifteen, he entered Lái Thiêu Seminary but had to return home after only a few months to assist his parents in raising his siblings.

In 1833, he married a young woman from the Thành parish, Long Điền village, Phước Tuy district (Bà Rịa). His family life was harmonious, and four children were born in succession. As a merchant who had to travel far, he faltered and fell into sin at one point. But upon awakening, he resolutely abandoned his wrongdoing, returned to his wife and children with renewed love, and earnestly taught them to live a virtuous life.

Mr. Gẫm owned a large ghe bầu (a type of traditional cargo boat) and was highly skilled in river navigation. On that very boat, he fearlessly transported Bishop Lefèbvre—Ngãi, missionary Pierre Duclos—Lộ, and three seminarians, as well as religious images, liturgical objects, Mass wine, and devotional books.

Upon returning, his boat was discovered by a patrol. A search was conducted, and two French priests were found aboard. He pleaded and offered each of the soldiers a tael of silver, but they refused and took the boat to Cầu Gọ. The bishop, missionary Lộ, and everyone else on the boat were unharmed; only the boatman Gẫm was arrested and placed in the cangue.

For more than twenty days he was interrogated and subjected to two or three dozen lashes, yet Mr. Gẫm remained steadfast and unshaken in his faith. The mandarin convicted him of smuggling, of secretly transporting Westerners and Western books, and then requested an execution order from the imperial capital.

On May 11, 1847, at the execution ground of Da Còm market (Chợ Đũi), soldiers spread out a mat, removed his shackles, and untied his bonds. The boatman Gẫm knelt, bowed his head, beat his breast in contrition, and received the death sentence. His remains were interred at Mật Cật. Later, Bishop Lefèbvre—Ngãi had them reburied on the former church grounds of Chợ Quán parish.

On May 27, 1900, the merchant from years past was beatified. And on June 19, 1988, he was officially canonized as a saint.