He will be based in DigitasLBi’s London office and will report to Ed Beard, the head of creative strategy.
At JWT, Carr led digital strategy for Johnson & Johnson in EMEA and the Nordics.
Last year, he was awarded a Gold APG Award for his work on the Benadryl Social Pollen Count app and was named the Google Planning Innovator of the Year 2013.
Prior to JWT, Carr worked at Chemistry, now Publicis Chemistry, for three years in roles including head of digital and digital strategy director. He previously worked at Publicis Dialog and for the British Army.
Fern Miller, the chief strategy and insight officer, international, at DigitasLBi, said: "David is a rare hybrid: a brand strategist with a user experience and design background who is capable of truly making brands live their promise through digital channels.
"His passion for creating useful and delightful work with the power to transform businesses makes him a great addition to our team."