After a litterature degree in the French university of Sorbonne (Paris), Xavier decides to work in cinema and starts to direct documentaries and short films.
In 1993, he directs his first short film "Le Condamné" with Philippe Léotard and Christine Boisson, an adaptation of a short story by Jean-Paul Dubois.He then directs "J'aime beaucoup ce que vous faites" with Mathilde Seigner, and later "Dialogue au sommet", with François Cluzet. In 1998, "L'Interview" with Mathieu Amalric wins the short film Palme d'Or as well as a César.
In 2003 he directs his first feature film, "Les Corps impatients", with actors Laura Smet and Nicolas Duvauchelle, both of whom he also includes in the cast for his second film, "Une aventure" with Ludivine Sagnier.
Xavier Giannoli then directs Cécile de France and Gérard Depardieu in "Quand j'étais chanteur" in 2006.
Based on a true story which happened in the north of France, "À l'origine" pictures François Cluzet as a crook who decides to carry on with an abandonned highway building project.
Associate producer for Valérie Donzelli's second film "La Guerre est déclarée" in 2011, he directs "Superstar" in 2012, with actor Kad Merad.
In 2015, he shoots his sixth film, "Marguerite", a period film inspired by the life of american classical singer Florence Foster Jenkins, known for singing off-key. Catherine Frot plays the part of Florence.
In "L'Apparition" (2018), he trusts Vincent Lindon with the part of a war-zone journalist appointed by the Vatican to inquire into the appearance of the Virgin Mary to a young girl.