Waddington will join Metia Group in January after spending nearly six years at Ketchum as chief engagement officer and European digital and social media director. His final day at Ketchum is 31 December.
At Metia Group, he will be responsible for leading a team of 60 people, managing the development and delivery of content marketing, social media, lead generation and communications campaigns.
Metia’s capabilities include social media analytics and insight, an international content network, content planning and optimisation, media strategy, web design and development.
In the past two years the agency has delivered campaigns in 88 countries in 39 languages for clients including Amazon, Dell, Microsoft and BMW.
"If you were asked to design a blueprint for a modern agency it would look a lot like Metia," Waddington said.
"Its expertise in analytics, content and technology, combined with intellectual property in planning, optimisation and reporting tools, and an international content network gives it a rock solid point of differentiation and significant opportunity for growth. I can’t wait to get cracking in my new role."
Metia Group founder Steve Ellis added: "He is a great addition to our senior leadership team. Stephen’s experience at helping global brands to tell their story through digital and social channels is a perfect fit to our strengths and capabilities."
Prior to Ketchum, Waddington co-founded and managed two agencies, Rainier PR in 1998, and Speed in 2009. He is a past president of the CIPR, a fellow of the CIPR and PRCA and has written eight books on marketing and public relations.