Stewart joined Chelsea from Monaco in 2022 and worked alongside fellow sporting director Paul Winstanley. His departure is not understood to have been caused by an internal dispute, with the change instead described as an evolution of the club's sporting structure.
Stewart does not have a confirmed departure date and could remain in attendance for matches in the short term, but he is expected to leave with Chelsea's approval.
He had a contract running until 2031, making his exit the first significant change since Clearlake Capital took full control of the club.
There are no plans to appoint a direct replacement for Stewart. Winstanley is expected to work more closely with Joe Shields and Sam Jewell, while former Liverpool sporting director Dave Fallows will remain part of the leadership group.
Shields and Jewell already have major responsibilities within Chelsea's recruitment operation. Jewell has a global role that includes sister club Strasbourg, while Shields also oversees the academy.
Stewart's remit included working with the data department, meaning some of those duties will now be absorbed by his colleagues as Chelsea adjusts its structure.
The sporting leadership team works closely with Chelsea manager Xabi Alonso and reports to Behdad Eghbali, who has become the most powerful figure at the club following Todd Boehly's departure.
Eghbali spoke earlier this year about the need to “tweak” Chelsea's model as the club seeks to progress.
Stewart leaves with extensive experience across European football. Before joining Chelsea, he worked as technical director at Monaco, global head of scouting at Red Bull Soccer International and head of performance analysis at Manchester City.
His relationship with Winstanley dates back around two decades, when the pair worked as match analysts at Hull and Wigan respectively.
Their time together at Chelsea included major successes, most notably the 2025 Club World Cup victory, when Chelsea beat Paris Saint-Germain 3-0 in the final.