Izzard-Brown will join McCann in January and will be responsible for all of the agency’s clients, which include Subway and Microsoft. He will report to the chief executive, Zaid Al-Zaidy.
Al-Zaidy moved from TBWA\London to McCann in May 2013 to be the chief strategy officer, but was promoted to chief executive five months later.
Izzard-Brown had been at Wieden & Kennedy since 2008, when he joined as a senior account planner. At W&K, Izzard-Brown handled Arla.
Al-Zaidy said: "Theo is a rare find. His track record is enviable and he has intellect, warmth and charm. I’m delighted to have tempted him to join us."
Before W&K, Izzard-Brown worked at Agency Republic as a digital account planner. He said: "What Zaid and the team at McCann London are doing right now is incredibly exciting. The invitation to join and help shape the agency’s next chapter is too big an opportunity to miss and one I intend to make the very most of."