After two-plus decades, Shake Shack CEO Randy Garutti announced on Monday morning he plans to retire in 2024 “upon the selection of his successor.” Garutti, who joined Danny Meyer’s Union Square Hospitality Group 24 years ago as its youngest general manager in company history, working at Tabla and Union Square Café, rose to director of operations for USHG’s fine-dining restaurants. In 2001, Shake Shack rolled out as a hot dog cart from Eleven Madison Park’s kitchen. Three years later, when it evolved into a permanent kiosk, Garutti asked to take the helm. He led the expansion nearly five years later into a multi-unit fast casual that has scaled beyond 500 stores over the past 20 years.

“It has been my honor to lead the talented Shake Shack team from our humble beginnings as a hot dog cart in Madison Square Park in New York City to the public company we are today. Together, we have achieved more than anyone dreamed, delighting communities across 18 countries, 33 states and more than 500 Shacks, while targeting to surpass $1 billion in revenue this year,” Garutti said in a statement. “I am most proud of the growth opportunities we created for our team members at every level and our shared commitment to uplift and take care of each other, our guests, our communities, our suppliers, and our shareholders.”

READ MORE: Shake Shack, Now 500 Locations Strong, Keeps Learning and Growing

The company’s board said Monday it’s launched an external search led by Korn Ferry to identify Garutti’s successor. Meyer will oversee the search committee alongside independent directors Chuck Chapman, Jeff Lawrence, Lori George, and Josh Silverman.

“I don’t have adequate words to express the gratitude I feel for having Randy as my colleague and partner for all these years,” Meyer said in a statement, adding Garutti “has more than earned the richly deserved opportunity to think about his next act.”

“He has built and led a globally beloved brand whose rich culture has deep roots and he has paved the way for our next CEO to build on a rock-solid foundation,” Meyer continued. “The board and I are now excited to launch a search for his successor, and are heartened that Randy will be at the helm until his successor begins.”

Garutti will continue as CEO and as an executive board member through the search. Shake Shack also intends to retain him as an adviser through the end of 2024 “to ensure a proper transition.”

Garutti penned a letter to the company as well. In it, he said he believed it was “time for the company to benefit from its next generation of leaders.”

“I never quite knew when this day would come, but in my heart, I’ve arrived at the realization that for me, my family and the company, this is the right time,” he wrote.

Garutti recalled Meyer hiring him 24 years ago, unsure if Garutti was ready, but deciding to give him a shot anyway at Tabla, the Indian restaurant fronting Madison Square Park. “For years, USHG was strictly a fine-dining company, building New York’s most beloved one-of-a-kind restaurants. That was until 2001, when Danny, in supporting the rejuvenation of the Park, asked the team to build a hot dog cart as part of an art project,” Garutti said. “Turns out people loved our hot dogs, which we cooked in the private dining kitchen of the renowned Eleven Madison Park restaurant. For three summers, our teams helped raise money for the Park and provided joy for our community selling dogs, lemonades, and more.”

Meyer famously sketched out Shake Shack’s permanent kiosk menu in pencil. It arrived in 2004 as a one-off project meant to activate and raise money for the Park.

Garutti was walking home in 2007 on the Upper West Side and saw a “for rent” sign on a storefront. He called Meyer and they set into motion the second Shake Shack. The company went public in early 2015.

“Shake Shack has been built to last,” Garutti said. “With each of us holding a place in the cornerstone of its foundation, building together, one brick, one team member, one guest, one community, and one burger at a time. I learned a long time ago that anything in life can be achieved when led by one person with effort and enthusiasm. It’s all we can really control in life. Today, I ask you to be that one person with enthusiasm in your work, on your shift, and for each other. With that, Shake Shack can achieve anything and so can you.”

Shake Shack opened 10 corporate and 15 licensed locations in Q3—the brand’s most recent reporting period—and is on track to debut about 80 total stores systemwide this year, or roughly 18 percent unit growth. About the same number and split is expected for 2024. Twenty corporate Shake Shacks were under construction as of November. Presently, about 40 percent of the fast casual’s sales stem from licensed operations, of which there are 215.

That 500 figure, which was just announced recently, is double from four years ago.

Shake Shack’s revenue grew 21 percent in Q3 to $276 million, with 2.3 percent same-store sales growth, inclusive of negative traffic of 4.2 percent and price/mix growth of 6.5 percent (the brand had high-single digit menu price in the quarter and took 1 percent at the end of October as well).

In-store sales rose 9 percent, year-over-year—a figure that benefitted from positive mix as Shake Shack’s kiosk retrofit progresses. Kiosks account for more than half of in-store business and sales through the channel hiked 140 percent versus Q3 2022. Average weekly sales hit $74,000, annualizing to $3.9 million average-unit volumes.