In his new role Douglas will lead the strategic direction of the burgeoning agency, which launched in December and works with brands including the Movember Foundation.
Douglas will aim to use his experience across media and creative to bring the two disciplines closer together for the benefit of the shop's clients.
TBWA\London appointed Douglas as its executive creative director in September 2015, just seven months after he joined Havas Media Group as its chief strategy officer. Douglas officially left TBWA\London yesterday.
Henry Daglish, former managing director of Arena Media and founder of Bountiful Cow, said: "I'm delighted Graeme shares my vision for where I believe this business needs to go, a core element of which is a much more fluid and productive relationship between media and creative.
"I don't think there's anyone better-placed in the industry than him to help make that happen. His range of experience and talent gives him unique insight into both worlds and the benefit to our product will be significant."
After starting his career in media, Douglas moved to Wieden & Kennedy in 2009, where he rose to creative director. His work includes Honda’s "The other side" campaign, which picked up five gold Lions in Cannes.
Douglas, who joins Bountiful Cow today, said: "Independence can't be faked, or bought, or sold. You know it when you see it – you feel it. I believe it's the key to good people making great decisions that lead to amazing work and it's what I felt when I met Henry to talk about his plans for Bountiful Cow. It's real.
"We believe independence, integrity and freedom is what this industry needs more of and it's impossible to overstate how excited and privileged I am to be a part of this journey from the beginning."
Both Douglas and Daglish declined to comment about whether he will have a stake in the shop.