[3] Born in New York City to Haitian immigrants, Gilles was raised in Montreal, Quebec.

When he was fourteen years old, his aunt Gisele Mouscardy sent one of his sketches to then Chrysler chairman Lee Iacocca.

[9] In August 2008, he replaced the retiring Trevor Creed as Senior Vice President of Design.

[11] After four years as the CEO of the SRT and motorsports division, he was promoted to the head of design for Fiat Chrysler Automobiles.

In 2021, the merger of French-based PSA Group with Fiat Chrysler automotive led to the creation of Stellantis N.V., where Gilles became the chief design officer.

While beginning his career, he led the interior design of the Viper GTS/R, Dodge ESX2 Concept, Jeep Jeepster Prototypes.