North joins the agency from the digital shop VML London, where he was the planning director.
At CMW, North will be responsible for working on a number of the agency’s FMCG clients such as Kellogg, Allied Bakeries and Cadbury.
North replaces Steve Taylor, who left CMW in November last year to join the media agency PHD as its head of digital planning.
During his time at VML, North led strategy for clients including Microsoft, Vodafone and Xbox, and also established an in-house social media practice offering analytics, listening and activation services.
North’s agency career spans 18 years, including a four-year stint at Archibald Ingall Stretton, as well as positions at OgilvyOne and TBWA.
Liz Wilson, the chief executive of CMW, said: "Matt brings a healthy balance of big-brand thinking and cutting-edge digital expertise that makes him equally at home in every channel.
"Matt has a great mix of client experience. He also has an impressive track record of delivering new business and playing a lead role in award-winning work."
North said: "CMW has a great new energy so I’m looking forward to making a strategic contribution as well as working with an exceptional calibre of client."