Rise, which was launched late last year by Simon Matthews, the former Optimedia managing director, and Andrew Goulborn, the former Saatchi & Saatchi communications director, will work across Reckitt's brands.
The agency will work with Reckitt's global brand teams and its creative agency networks, Euro RSCG and J. Walter Thompson.
Rise's task is to explore how Reckitt can better target its customers and find new ways of communicating with them.
Goulborn said: "We believe that we can help to drive further value creation within the Reckitt Benckiser business and connect really effectively with customers."
Reckitt appointed Euro RSCG and JWT globally last year after a review process that saw McCann-Erickson lose its hold on the business.