Brooks, who left GSK in November 2010 after 11 years at the company, takes up the role of non-executive director at the agency this month.
He will have responsibility for strategy development, client relationships and projects.
He will report to the agency’s chief executive, David Gray.
Brooks managed more than 30 departments while at GSK, where he was responsible for brand marketing, innovation, research and expert marketing, and has been working as a consultant since leaving the company.
Gray said: "We have known Tim for a long time and we feel that his commercial input and extensive marketing and healthcare experience will help to take the business forward particularly within our health and wellbeing practice areas.
"This is one of a number of steps we are undertaking to enhance our ability to add value to our clients."
Creative Leap has worked with a range of healthcare clients, form GSK to Alliance Boots, Bupa, Johnson & Johnson and Reckitt Benckiser.
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This article was first published on campaignlive.co.uk