Burger King chief executive Brad Blum has quit his post over "strategic differences" with the company board, the fast food group has said.
Sales hit four and a half year highs during Mr Blum's time at the group
Mr Blum's departure comes just 18 months after he joined the struggling company, which was spun off from UK conglomerate Diageo in 2002.
Burger King added the search for his replacement was underway, adding it hoped to find a new chief by August.
Senior management will oversee the business until a replacement is found.
The fast food chain is owned by a private equity group made up of Goldman Sachs Capital Partners, Texas Pacific Group and Bain Capital.
Owen Blicksilver, spokesman for Texas Pacific, confirmed that talks with some potential chief executive candidates had taken place, but refused to elaborate on the meetings.
Mr Blum joined the company in 2003 from Darden Restaurants where he held the post of vice chairman.
During his time at Burger King, the group revamped its menus and switched advertising agencies.
The changes are credited with the company seeing its biggest rise in same store sales at its US restaurants for more than four-and-a-half years in May.
In a statement Mr Blum said: "While there remains much work to be done, good progress is being achieved and the team is committed to accelerating this growth.
"I have enjoyed my relationship with the company's many employees and franchisees and wish to thank them for their support in building the Burger King brand."
However analysts have voiced concerns that Mr Blum's resignation could provide a boost to the company's rivals such as Wendy's International and Jack In The Box.
They claim the "revolving door" policy that has seen nine
different chief executives in the past 15 years may be behind the group's decline in market share in recent years.
Burger King operates some 11,000 restaurants in 60 countries itself or through franchisees.