The chef, who has run a fine dining residency above the gastropub since March, will be taking full control of its operations from January 2018.
The pop-up will continue as a permanent restaurant, serving a weekly-changing seven-course tasting menu, followed by the launch of a brunch offer in March.
The bar area will offer ‘lighter refreshments’ while the main gastro pub continues to run downstairs.
“Following the continued success of my pop-up restaurant on the top floor, it seems natural to make this a permanent fixture,” says Walker.
“I'm also delighted to take over of the rest of The Riverside Inn and can't wait to start serving amazing dishes in the pub downstairs.
“We hope as an independent restaurant with local suppliers, the people in Chelmsford and the surrounding areas will get behind us and really enjoy what we are about to do.”
Walker reached the semi-finals of MasterChef: The Professionals in 2015 and was previously head chef at The Woodford in London and King’s College Cambridge.
The Riverside Inn is part of The Blue Group, a six-strong restaurant group based in Essex.