Leavitt will be responsible for helping to drive overall business strategy for Pollen.
She joins the agency with 25 years of marketing experience, which spans across a number of industry sectors including FMCG, beauty, healthcare, financial services and retail.
Dan Dimmock, partner and director of strategic development at Pollen, said: "Vicky brings with her a wealth of blue-chip marketing and management experience from a career that has spanned all marketing disciplines and much of the globe.
"She combines this incredible expertise with unstoppable enthusiasm and a strong track record of business growth."
Leavitt began her career in brand management with Procter & Gamble at their worldwide headquarters in Cincinnati.
This was followed by five years in product management and marketing with Kraft, overseeing new products as well as large established businesses.
She has also held senior agency management positions within Omnicom, Interpublic and Lighthouse/Cordiant (now part of WPP).
Most recently, Leavitt has been at the helm of two of Omnicom's London-based branding firms as chief executive of New Solutions and managing director EMEA for Siegel+Gale.
Leavitt said: "This is an exciting role for me and I am particularly looking forward to working with the talented Pollen management team to build on the success they have already achieved, while also raising their profile within the industry."