Mariotti was born in Las Matas de Farfán to Charles N. Mariotti Martini, an Italian-Dominican agronomist, and Enoé L. Tapia Suero. By his mother, Mariotti is descended from , who is considered a Dominican independence war hero against Haiti, and from the Dominican President Ulises Heureaux (Heureaux was Ogando’s son-in-law, and Mariotti’s great-great-grandfather).