He was born around 1070 at Tresino, in Lucania (currently part of the comune of Castellabate), to the noble Gentilcore family.

At the age of seven, he was entrusted to the care of abbot of Cava, Leo I. Constabilis then became a monk at the abbey.

He followed the Benedictine Rule zealously and was entrusted by the abbot to manage important negotiations and transactions on behalf of the abbey.

Constabilis is venerated as the patron saint of Castellabate, for the reason that he founded the town.

He died at the age of fifty-three and was buried in the church overhanging the grotto of Arsicia that had been used by the founder of the abbey, Alferius.