Chard joins from Leo Burnett, where he was the regional planning director for Europe, the Middle East and Africa.
Initially, he will work out of the London office alongside Tony Wright, the network's chief executive. Chard will be permanently based in New York from the autumn.
Chard will work across all of the network's clients, which include Unilever, Nestle and Saab. He will be responsible for developing and implementing strategy across these businesses globally.
Chard has spent the past seven years at Leo Burnett. He began there in 1998 as a planning director for Leo Burnett Paris. Four years later, he was promoted to the regional planning director role.
Earlier positions include European planning director for DMB&B and planning director for Lowe & Partners Frankfurt. Chard was also a planner for Young & Rubicam Europe and has worked across clients including Procter & Gamble, Mars and Ford.
Wright said: "Having spent so much of my time in planning, I knew Lowe Worldwide's new management team would not be complete without a chief strategy officer. Chris will ensure that Lowe's insights and strategies are second to no other agency network."
Chard added: "Any director of strategic planning would jump at the chance to report to a chief executive with Tony's history and success in planning. Making sure that the planning discipline has as enviable a reputation will be my biggest challenge."