Impatient over the slow pace of its sales recovery, Gap Inc. said the head of Gap North America will step down as the apparel brand tries to reinvigorate its merchandise and flagging stock price.

Marka Hansen, president of Gap North America since 2007, is leaving Friday and will be replaced by an insider to be named shortly, Gap said yesterday.

Hansen — a 24-year company veteran who held top roles at Gap, Banana Republic and in the International division — was a merchandiser charged with attracting new design talent to bring the most appealing line of clothing into stores and simplifying operations.

Gap, which began in 1969 in San Francisco as a seller of jeans, grew to be the best-known retailer in the United States during the 1980s and 1990s with its combination of khaki pants and white T-shirts that defined casual American style.

But that luster eventually faded as more competition entered the market, while a series of executive changes and confusion over strategy soon translated to lackluster clothing on racks that did not appeal to Gap’s loyal customers.

Hansen’s tenure helped stem that tide and wrested Gap from a protracted period of falling same-store sales. But still, the performance of stores on her watch has been inconsistent.