Gavin Cox has been appointed chief executive at Famously Proper, the owner of the Byron burger and Mother Clucker restaurant brands.
He replaces Simon Wilkinson, who joined Byron three years ago and helped steer the business when it was bought out of administration in a £4m pre-pack sale by Famously Proper last year.
Wikinson also oversaw the group's acquisition of fried chicken brand Mother Clucker for an undisclosed sum in May.
Cox has experience working in food organisations including Adelie Foods, McCambridge Group and Street Eats. Famously Proper said his expertise in business growth fits with its plans for the "next stage of development" of both its restaurant brands.
Wilkinson said: "I have reached a stage in my life when I am looking for a change of direction. I believe my job is done and I am confident I am leaving Famously Proper in a very strong position to capitalise on future growth opportunities."
Famously Proper chairman Sandeep Vyas added: "We thank Simon very much for his hard work and commitment to the business and wish him the very best for the future.
"As the company shifts into the next phase of its development and expansion, we are delighted to have Gavin Cox at the helm, and we will continue to execute on our strategy of building a category leading platform delivering great experience to our consumers through destination restaurants and frictionless on demand digital access to great tasting food."
Byron was founded by Tom Byng in 2007 and now runs 21 restaurants and seven delivery-only locations across the UK.
Fried chicken brand Mother Clucker launched at London's Old Truman Brewery in 2013 and has since opened at Flat Iron Square and via Deliveroo Editions in Whitechapel in the capital.