The French chef joined the Holborn site in 2015, replacing Bjorn van der Horst, and oversaw its restaurants and bars including The Mirror Room.
Chaignot gave up a postgraduate degree in pharmaceutical studies to pursue a career in cooking, training at the École Grégoire-Ferrandi in France.
She took part in the 2001 Bocuse d’Or, and went on to cook with Alain Ducasse and Jean-François Piège at Hôtel Plaza Athénée, before joining Le Bristol and Le Meurice in Paris.
Prior to moving to London to oversee Rosewood, Chaignot worked as executive chef at Hotel Raphael in Paris for two years.
Chaignot is yet to confirm her next move, though a spokeswoman for Rosewood London said the hotel would be announcing her replacement shortly.