By Maarten van Tartwijk and Bart Koster

AMSTERDAM--Food retailer Koninklijke Ahold NV said Thursday the chief executive of its flagship Albert Heijn supermarket chain in the Netherlands would step down after a lackluster performance.

Sander van der Laan, an Ahold veteran who took the helm of the Netherlands' largest supermarket chain in 2011, will leave the company on Feb. 1. His resignation was "mutually agreed" after the business lost market share and posted a series of sluggish quarterly sales, said spokesman Tim van der Zanden.

Albert Heijn has struggled to keep up with increasing competition from discounters and high-end food retailers. It has pledged to revamp its stores and invest in online channels to drive future sales growth.

"Albert Heijn had a good fourth quarter ... but hasn't performed optimally in the past year and a half," Mr. van der Zanden said. "The shopping experience of customers wasn't good and the brand positioning wasn't right," he added.

Mr. van der Laan, who wasn't available for comment, will be replaced by Wouter Kolk, who currently heads Albert Heijn's specialty stores and new markets operations.

Ahold on Thursday disclosed that its operations in the Netherlands, including Albert Heijn, reported 4.5% growth in net sales in the fourth quarter to EUR2.84 billion ($3.45 billion), beating analyst expectations. But the increase was driven by aggressive promotional campaigns during the holiday season, which will have a negative impact on profit margins.

"Retailing in a mature and difficult economic environment remains a balancing act between volume and margin," said SNS Securities, a Dutch brokerage.

Stronger sales in the Netherlands lifted Ahold's overall sales to EUR8.06 billion, an 8% increase compared with the same period a year earlier.

In the U.S., where the retailer generates about 60% of its revenue, business was less robust, partly as a result of the weaker euro against the dollar. Sales fell 0.5% to EUR5.98 billion at constant exchange rates, and Ahold said it lost market share during the fourth quarter.

The company will report annual earnings on Feb. 26.

Write to Maarten van Tartwijk at maarten.vantartwijk@wsj.com and Bart Koster at bart.koster@wsj.com