Chicourel, who has been "invited to push the reset button" at M&C Saatchi, replaces Gaby Bell, who quit the ad agency in July last year to start a new business.
She will begin her new role in March and will be responsible for thought leadership across the agency’s client base, as well as developing "Brutal Simplicity of Thought" – M&C Saatchi’s founding ethos.
It is the second key appointment by chief executive Giles Hedger, who joined M&C Saatchi from FCB Inferno in May 2017. Kate Bosomworth, the PR chief who led Sport England's "This girl can" campaign, will begin her role as chief marketing officer on 8 January.
M&C Saatchi came under fire from across the industry last year over an opinion piece in Campaign in which chief creative officer Justin Tindall complained of being "bored with prioritising diversity over talent". Tindall later apologised and was given a vote of confidence from global chief executive Moray MacLennan.
The agency appeared to acknowledge the issue in a statement today by describing Chicourel as "most proud" of nurturing a planning department at Saatchis that is "built on equality with a high standard in strategy and creative output".
Chicourel said: "For me personally this is one of those singular moments in life when a set of people with unassailable spirits invite you to push the reset button and shape the future of a well-known London agency."
Like Bell, Chicourel will be one of the five shareholders under the terms of the management buyout announced in 2016, alongside Hedger, Tindall, group chairman Tim Duffy, and managing director Tom Firth.
At Saatchi & Saatchi, Chicourel led the strategy department alongside fellow joint head of planning Sam Wise and reporting into chairman and chief strategy officer Richard Huntingdon.
She joined the agency in 2014 as a planning partner, working on accounts for Homeaway, Marie Curie, Richmond Sausages and Haagen-Dazs. She was appointed joint head of planning in March 2017.
She is credited with winning an IPA Effectiveness award, a Cannes Lion and a YouTubeWorks Grand Prix for her work on Mattesons, as well as further creative awards for Homeaway. As planning partner Chicourel also worked directly on the Haagen-Dazs and Richmond Sausages accounts.
Chicourel previously worked at Abbott Mead Vickers BBDO for three years as board planning director and has also held strategy roles at Bartle Bogle Hegarty, Publicis London, McCann and J Walter Thompson.
Hedger added: "Raquel is a rare combination of reductive pedigree and expansive flair. She is the perfect embodiment of Brutal Simplicity of Thought as it enters its next chapter."