The 33-year-old Arnault-Gancia, who is the daughter of LVMH Moët Hennessy Louis Vuitton chairman Bernard Arnault, was formerly senior vice president of marketing at Dior.
"I am pleased to take on new responsibilities at Christian Dior, especially at such an exciting time for the brand, which is experiencing substantial growth," Arnault-Gancia told WWD Wednesday. "I intend to actively pursue the development of Christian Dior."
The appointment is effective immediately.
Dior's president and chief executive officer, Sidney Toledano, said Arnault-Gancia would contribute "strongly" to the brand's development.
A graduate of Paris' EDHEC Business School and the London School of Economics, Arnault-Gancia started her career at the McKinsey consulting firm. She has worked at Dior in a variety of executive roles since 2001, and has been a member of LVMH's board since 2003.
Arnault-Gancia is also on the board of Emilio Pucci and Spanish leather goods and fashion brand Loewe.