Frédéric Arnault was born on 7 November 1994 in Neuilly-sur-Seine, the elder of Bernard Arnault's two sons with the Canadian pianist Hélène Mercier. He studied at the Lycée Saint-Louis-de-Gonzague and the Lycée Louis-le-Grand, and graduated from the École Polytechnique in applied mathematics and computer science. An amateur pianist since childhood, he has given several concerts.
He began his career at McKinsey and then at Facebook's artificial intelligence research centre, and in 2017 co-founded the mobile payment start-up NEOS, sold to BNP Paribas about eighteen months later. In 2018 he joined TAG Heuer as head of strategy and digital, and on 4 June 2020 became its chief executive, developing its connected watches and pushing it upmarket, including with new high-end Monaco models. In January 2024 he became chief executive of LVMH Watches, covering TAG Heuer, Hublot and Zenith, and oversaw the acquisition of L'Epée 1839; he also joined LVMH's board and became deputy managing director of the family holding Financière Agache. LVMH also credits him with a key role in its global partnership with Formula 1.
LVMH announced in March 2025 that he would lead Loro Piana; after a transition with Damien Bertrand from 26 March, he became chief executive on 10 June 2025, reporting to Toni Belloni, chairman of LVMH Italy. In July 2025 a Milan court placed the company under judicial administration over alleged labour exploitation at subcontractors of an outside supplier; Loro Piana said it had cut ties within 24 hours of learning of them, and the measure, due to last until July 2026, was lifted early in April 2026. At the end of 2025 LVMH raised its stake from 85% to 94%. In September 2026 he opened an 8,000-square-metre knitwear plant at Ghemme in Piedmont, the largest investment in Loro Piana's history, which also houses its training school, the Accademia dei Mestieri.
French Wikipedia dates his appointment to April 2025 and English Wikipedia to May 2025; Casadi uses LVMH's effective date of 10 June 2025.