Alexandre Arnault was born on 5 May 1992 in Neuilly-sur-Seine, the son of LVMH's chairman Bernard Arnault and the Canadian pianist Hélène Mercier. He went to the lycée Saint-Louis-de-Gonzague and the lycée Louis-le-Grand in Paris, graduated from Télécom Paris and took a master's degree in innovation at the École Polytechnique, and did internships at McKinsey and KKR. His whole career has been within LVMH companies.
He is said to have led the two-year negotiations by which LVMH bought 80% of the Cologne luggage maker Rimowa, completed in January 2017, and became co-chief executive alongside Dieter Morszeck until Morszeck left in May 2018. He reshaped the brand. He opened its Paris flagship in March 2017 and its first Milan store in 2019, and in March 2018 terminated its European dealer contracts so they could be reissued on stricter terms. He hired outsiders, among them the Nest designer Rochus Jacob as chief product officer and Hector Muelas as chief brand officer. In 2018 he launched a new visual identity by the London studio Commission for the company's 120th anniversary, and a run of collaborations beginning with Supreme and followed by Off-White, Fendi and Dior. From 2019 to 2021 he also sat on Carrefour's board in place of his father.
In January 2021 he handed Rimowa to Hugues Bonnet-Masimbert, staying on as non-executive chairman, and became executive vice-president of product, communications and industrial at Tiffany & Co., which LVMH had just bought. In 2023 Fast Company credited him with much of Tiffany's growth, while later press accounts questioned the turnaround. On 1 February 2025 he became deputy chief executive of LVMH's wine and spirits division, Moët Hennessy, alongside Jean-Jacques Guiony. He also sits on the boards of Moncler and Birkenstock, and in September 2026 he joined the board of Nike.
French Wikipedia flags his degrees as unevenly sourced. The Nike board appointment is reported there and has not been checked against a Nike filing.