Sam Noble, one of the founders of Iris, has died aged 47 after a five-year battle with cancer.
The agency is marking the contribution of "The Sage", as he was known, by establishing an internal award to celebrate breakthrough thinking, called The Noble Prize.
Noble's role at Iris changed with its international expansion, taking him from joint MD of the London agency to global chief strategy officer in 2013 and deputy global CEO in 2016.
However, he was forced to leave the business five years ago, aged 42, after being diagnosed with stage-four bowel cancer.
In a LinkedIn post, a spokesperson for Iris said: “Whether he was running marathons across the Sahara or driving some of our proudest moments as a business, his impact was felt by all around him.”
Claire Humphris, chief executive and co-founder of Iris London, added: "Sam leaves a huge hole in the Iris family. We called him The Sage for good reason.
"His fierce intelligence, coupled with unshakeable integrity and talent for words, meant he was an enlightened and inspirational leader. He always spoke about legacy… what he left behind for others was his driving force.
"He was immensely proud of what he had achieved with Iris and for good reason. We were just so lucky that he chose to be with us for as long as he could. His ideas and impact will continue for many years to come."
After his diagnosis, Noble published two poetry anthologies – Still Life and Planting Trees – to raise money for Children with Cancer UK. He passed away in early August.