Gennaro Maria Sarnelli was born on September 12, 1702 at Ciorani in the Kingdom of Naples. Educated as a lawyer at Naples, Gennaro undertook the religious vocation and was ordained priest in 1732.
In 1733, at Naples, Gennaro met St. Alphonsus Liguori (see his existing entry) and became one of the co-founders of the Redemptorist Congregation. From 1736, Gennaro undertook the Redemptorist popular-mission ministry across the Kingdom of Naples.
Gennaro became famous during his lifetime for the anti-prostitution reform ministry — personally organizing the rehabilitation of Neapolitan prostitutes, establishing the institutions for reformed prostitutes, and undertaking the public denunciation of the Neapolitan sex industry.
Gennaro composed multiple pastoral treatises — most famously 'L'Ecclesiastico Cristiano' ('The Christian Ecclesiastic') and 'La Vera Sposa' ('The True Bride'). He died at Naples on June 30, 1744 at the age of 41.

