The Frenchman, who has worked at the sky-high dining room at the London Hilton on Park Lane since it opened in 2006, made the announced on social media on Saturday (7 December).
He wrote: “The time has come to say good bye to all my friends and colleagues after an incredible 14 years journey @galvinatwindows.
“I would like to take this opportunity to thank everyone who has supported me over the years and helped us create amazing experiences and deliver excellence to all our wonderful guests on the 28th floor @londonhiltonpl.
“I will always remember what you did - your selfless hospitality, kindness, hard-work, focus, professionalism and dedication. Thank YOU!
Sirieix has yet to confirm his future plans but added: “And now onto another adventure.... 2020 here I come #watchthisspace.”
The maître d' arrived in London in 1992 and worked at La Tante Claire with Pierre Koffmann, Le Gavroche, Sartoria and Bluebird Café.
He joined Galvin at Windows in 2006, and helped the restaurant maintain a Michelin star for 13 years until it lost the accolade in the 2020 edition of the Michelin Guide Great Britain and Ireland.
Sirieix has also written a book and launched a television career that has seen him front programmes including Channel 4’s First Dates and the BBC’s My Million Pound Menu.
He is involved in numerous industry training schemes including Galvin’s Chance, which helps young people not in education or employment train in hospitality work, and National Waiter’s Day, which champions front of house careers.
Sirieix is also behind The Right Course, a programme that teaches prisoners about service and cooking with the dual aim of reducing re-offending and tackling the skills shortage in the hospitality industry.