Hardcastle is a former ITC national sales manager, and brings more than a decade’s additional experience to the role from his time with Gold Medal.
He has been appointed senior sales manager UK and Europe – all-inclusive, with a specific focus on Marriott’s All-Inclusive by Marriott Bonvoy operation.
His role will involve supporting growth, growing business with the trade through the platform, and establishing the brand as a "brand of choice" for all-inclusive travel.
Marriott said Hardcastle had developed "an intricate understanding" of the luxury travel trade.
Glynis Jeffery, Marriott International director of sales UK and Europe – all-inclusive, said: "This is an exciting time of change and growth for the All-Inclusive by Marriott Bonvoy portfolio.
"Jon has an excellent pedigree in the luxury travel trade sector, so having him on board to help drive that growth is wonderful – we are proud to have him on the team."
Hardcastle added: "Marriott and its many brands is a company I have always admired, so to be a part of its journey and growth is an honour for me, especially in destinations close to my heart – the Caribbean and Latin America."