The 75-year-old, who deftly managed to build a luxury brand over 48 years while also catering to the so-called aspirational shopper with lower priced brands like Chaps and Club Monaco, will step down in November but stay on as executive chairman and chief creative officer, the company said on Tuesday.

Shares of Ralph Lauren, (RL) which have fallen 44% so far in 2015 as the business has struggled, rose nearly 4% in after hours trading.

That’s because of who is taking the helm from Lauren: Stefan Larsson, the wizard who since joining Old Navy three years ago has transformed the brand into Gap Inc’s (GPS) star brand, handily outperforming its sister Gap and Banana Republic brands. Gap shares slipped on the news of his exit.

After a deep slump, Old Navy has over the past four years added $1 billion in sales and continued to grow quickly. Gap Inc has held up Old Navy’s processes to be better attuned to the latest fashions than those of its siblings, and as a model for the other brands to emulate. Prior to joining Old Navy, Larsson had a successful 15-year stint at H&M in his native Sweden.

The move is the latest major change at Ralph Lauren in recent years: Roger Farah, the former COO credited with turning Ralph Lauren into a juggernaut (Lauren was seen by many as a figurehead CEO, with the COO effectively the chief), stepped down three years ago. His replacement, Jackie Nemerov didn’t fare as well and will retire, though she will advise the company. She had restructured Ralph Lauren around global brands in the hopes of making the company more agile, but to little effect.

After years of torrid growth, Ralph Lauren’s growth has cooled. Revenue grew just 2.3% in its fiscal year 2015, which ended in March, to $7.6 billion, and net income fall nearly 10%. And analysts expect no revenue growth this year. Indeed, in the first quarter of this year, revenue declined 5% to $1.6 billion. The company has been hit by the effects of a strong dollar, but also aggressive promotional markdowns across a very competitive apparel industry.

“My job is to think always about the future of our company and how to move it forward. Stefan Larsson is exceptionally talented, and he will bring our company a fresh and exciting global perspective,” Ralph Lauren himself said in statement.

As for Old Navy, Jill Stanton, the brand’s executive vice president of global product, will lead the division while the company looks for a new global brand president. Her previous work includes almost 14 years as vice president and general manager of global apparel at Nike (NKE).