Marks joined OMG in 2014 following Omnicom’s acquisition of Mobile5, the global UX, design, and tech consultancy service that he co-founded. As CEO of OMG EMEA, he helped establish the group's Transact connected commerce and retail media consultancy in the region. He also co-architected the expansion of OMG’s TRKKN analytics and cloud consultancy from five European countries to 20 markets across APAC, EMEA, and North America.

Commenting on the promotion, Florian Adamski, Global CEO of Omnicom Media Group said, “Guy is one of our industry’s most entrepreneurial leaders, with an approach that transformed first OMD’s and subsequently Omnicom Media Group’s offering in EMEA over the past six years. By enabling our agencies to quickly identify, adapt, and respond in real-time to the challenges of a dramatically changing consumer marketplace, he’s unlocked growth for our clients and made OMG  the #1 media agency group for net new business in the EMEA region for the year-to-date, according to the most recent COMvergence reporting."  

Brown, who has served as PHD’s global CEO since 2019, is stepping down following almost four decades in the media industry – including 16 years in leadership positions with OMG – to focus on non-executive advisory roles at both the corporate and advocacy levels.

“The thread that can be pulled through all my professional experience is driving growth through transformation,” said Guy Marks. “As the CEO of PHD Worldwide – an agency that was born from a transformative concept of media as a strategic tool – my priority will be assuring that every PHD account team around the world has the talent, tools, technology, and collective commitment to excellence they need to deliver the  transformative ideas, solutions, and service that drive growth for our clients, our agency, and our people.” 

Marks, whose appointment is effective October 1, will be headquartered in London, reporting to Adamski. His successor as leader of OMG EMEA is expected to be named next week.