Moore will relocate from New York for the new position, which Ketchum said will focus on "delivering a differentiating pipeline of new skills, products and services", as well as offering strategy counsel to clients.
Moore, who starts at the agency on 29 May, joins from New York brand consultancy Wider Lens, where he was managing partner.
His other roles have included chief strategy officer at ad agency Lowe & Partners Worldwide; CEO of marketing agency StrawberryFrog NYC; and partner and chief strategy officer at marcoms consultancy Deutsch New York. Moore has served on the boards of PR agencies Burson-Marsteller and Weber Shandwick.
At Ketchum, Moore will lead a team of more than 20, comprised of social media and research analysts, insight and planning experts, designers and producers, the agency said.
He will report to Ketchum London CEO Jo-ann Robertson. They previously worked together at Weber Shandwick.
Ketchum said Moore "has both breadth and depth of experience to accelerate Ketchum towards the vision of being the best communications agency in London doing work that matters".
Further senior hires
Also joining the Omnicom agency’s London office are Florencia Lujani, senior strategist – influencer marketing at We Are Social, as influencer management associate; and Olly Smee, design director at BBH London, as content creative director.
Both are new roles; the latter is an upgrade from head of design. Lujani and Smee will join at the end of June.
These are the first major new positions at Ketchum London created under Robertson, who was promoted to UK boss In January.
She said: "The communications industry is in a full state of disruption with increasing emphasis on strategic, high-quality, purposeful, and quick-turnaround solutions. Insight-driven creativity is everything, and that is why we are making this significant hire now.
"Bert Moore is an innovator with proven business transformation success. We are very excited about the impact he will have on our clients, teams and agency as we make a rapid leap forward."
Moore said: "Having spent the past decade in brilliant creative advertising shops, I’m really looking forward to bringing those new skills to my familiar home. Technology may have levelled the playing field for all agencies, but the advocacy-driven approach of PR cultures is a distinct advantage. Ketchum combines a kindness and ambition that was magnetic to someone with creative restlessness."
Ketchum London is listed 16th in the most recent PRWeek UK Top 150 consultancies table, with revenue of an estimated £28m in 2017, a rise of more than nine per cent on the previous year.
The firm was a multiple winner at the PRWeek Global Awards 2018, which were held in London on Tuesday.