After 26 years as chair of Iris Worldwide, Ian Millner is stepping down from the U.K. agency he founded.

Millner built Iris from a start-up into a $100 million-plus global creative business, per Campaign. Twelve years ago, the agency joined Cheil Worldwide.

He will remain in a global advisory role.

Millner founded Iris in 1999 as an entrepreneurial challenger to traditional ad agencies, producing ideas people want to engage with. Its brand portfolio includes Samsung, Beam Suntory, Brita, Bentley and Beiersdorf. Today, the agency operates across 11 offices worldwide with more than 650 people.

His move follows the appointments of top-tier execs: Zoe Eagle was named CEO of Iris London, Jill Smith as CEO of Iris Americas and Menno Kluin as Global Chief Creative Officer. All work with Ben Essen, Global Chief Strategy Officer.

The team is responsible for the agency's recent rebrand and positioning:“Participate or Perish.”

Millner said: “It has been an incredible journey, and I’ve had the privilege of working with truly inspiring people all over the world. Iris joined Cheil 10 years ago, and it has been an enormously successful partnership. With Jill and Zoe in place, and with the revitalised proposition now in market, Iris is well positioned to continue to innovate and challenge the industry at a time when many agencies are facing an identity crisis. Playing it safe is more dangerous now than ever before.”

Eagle added: “Ian was one of the main reasons I joined Iris. He built the agency with an extraordinary entrepreneurial spirit and belief in creativity that continues to shape the business today. As we enter the next chapter, we’re focused on building on that legacy.”