Mariotti will join the winemaking department next to Dominique Dermarville until the end of 2019 before being named cellar master and wine director from January 1, 2020.
The 48-year-old began his career in champagne with Nicolas Feuillatte before moving to G.H. Mumm Maison.
Marc Gallot, president and CEO Veuve Clicquot, said: “I would like to thank most sincerely Dominique Demarville for his great contribution in the past 13 years to the unanimously recognised quality of our wines as well as the Maison influence across the world.”