Born on January 1, 1897, in An Giang Province, Diep was ordained in 1924 after completing his studies at Phnom Penh Major Seminary in Cambodia.

[2] Upon his return to Vietnam, Diep taught at a local seminary and served as a pastor of Tắc Sậy parish for 16 years.

Boss Cận went to general Phát and accused Diep and other Christians of colluding with the French who would exterminate the Cao Đài.

Although Catholic, because of his supposed "supernatural powers," he is also worshipped by people of folk religions, sometimes alongside non-Christian Indigenous Vietnamese divinities.

[6] On October 31, 2014, the Congregation for the Doctrine of the Faith issued a nihil obstat statement approving the process for Diep's canonization.